Breeding Hen Research Articles

Prevalence of Eimeria Species, Detected by ITS1-PCR Immobilized on FTA Cards, in Future Laying Hens and Breeding Hens in Six Provinces in Northeastern Algeria.

Avian coccidiosis is an important and widely distributed disease that affects global agricultural economies through losses. In Algeria, there is limited epidemiological and ecological knowledge about this disease and this hinders implementation of control strategies. A recent study, in Algeria, demonstrated a high prevalence and diversity of Eimeria species in broiler chickens. However, very little is known about the Eimeria species that exist on chicken farms raised on the floor and older than broiler chickens (for example, future laying hens and breeding hens) in Algeria. Samples were collected from 32 poultry farms located in 6 northeastern Algerian provinces (Algiers, Batna, Bejaia, Bordj Bou Arréridj, Jijel, Mila). These included 22 pre-laying pullet farms, with hens aged between 11 and 17 weeks, and 10 breeding hen farms with older hens (over 20 weeks). FTA cards were used to capture DNA and internal transcribed Spacer 1 PCR (ITS1-PCR) was used to determine the prevalence and composition of Eimeria species in the chickens. This showed the presence of six species of Eimeria with a diverse prevalence range. Eimeria necatrix (63%) was the most common species, followed by E. maxima (53%), E. tenella (31%), E. brunetti (19%), E. acervulina and E. mitis (both 0.3%). Eimeria praecox was absent. Eimeria infection affected all farms studied where co-infections by different Eimeria species (63%) were more frequent than single infections (38%). The number of oocyts, per ml of enriched oocyst suspension was higher in breeding hen farms compared to pre-laying pullet farms. This study, taken alongside a previous study involving broiler farms, demonstrated that the infection with this parasite is a significant problem in Algeria.

Migration patterns of breeding Hen Harriers Circus cyaneus in Spain

ABSTRACT Capsule Tracked Hen Harriers Circus cyaneus breeding in Spain winter either in the southern parts of the Iberian Peninsula or in Morocco, although migration timing and distances did not differ between birds using different wintering regions. Aims To study, for the first time, the migratory patterns of Hen Harriers breeding in Spain. Methods Eight breeding adult Hen Harriers were tagged in Spain with GPS/GSM transmitters between 2019 and 2022 to study autumn and spring migration between breeding areas in central or northern Spain, and wintering quarters in southern Spain and Morocco. Results Males and females did not differ significantly in their patterns of migration (dates for start and end of migration, duration, daily distance, and total distance) in either migratory period. Individuals started the autumn migration between July and January, with the peak migration in mid-October. Spring migration took place from February to April and peaked in mid-March. Mean (± sd) distances travelled were: daily distance 168.99 ± 80.10 km/day and total distance 995.07 ± 402.90 km in autumn, and 141.74 ± 41.41 km/day and 1035.26 ± 593.51 km in spring. Two types of migration patterns were found: intra-peninsular migration and migration to Morocco. Migration dates and distances did not differ significantly between individuals with intra-peninsular migration strategies and those migrating to Morocco. Conclusion These results are the first to describe the migratory behaviour of Spanish breeding Hen Harriers using satellite telemetry. Knowledge of migratory routes and behaviour are important for planning the conservation of species.

DISTILLER’S DRIED GRAINS SUPPLEMENTED Wz3ITH ENZYME COCKTAIL AND YEAST AFFECT EGG QUALITY, REPRODUCTIVE PERFORMANCE AND BLOOD PROFILE OF BREEDING HENS

This experiment aimed to examine the influences of distiller’s dried grains with solubles (DDGS) in breeding hen’s nutrition (0, 10, and 20%, respectively) with or without enzyme cocktail blend and yeast (Saccharomyces cerevisiae, SC) supplementation on the sustainability of eggs and semen quality, fertility and hatchability, and blood biochemistry. In total, 360, twenty weeks old indigenous Inshas breeding hens and 36 Inshas cocks (for natural mating) were used in the experiment. Inshas is a crossing breed that originated from mating Sinai and White Plymouth Rock breeds. Hens and cocks of all experimental groups had approximately similar initial body weights (1,560 ± 12.3 g) at the start of the experiment and were divided into 12 groups, each containing three replicates (10 hens + 1 cock). Moreover, 60 cocks were divided into 12 groups of five cocks each and housed individually in cages for semen quality estimation using the artificial collection technique. Increasing DDGS up to 20% in diets of breeding hens decreased (p≤0.05) eggshell thickness compared to 0 and 10% DDGS, but it elevated (p≤0.05) color of yolk and Haugh unit score during the storage period. Dietary treatments did not significantly affect the percentage fertility, hatchability, and abnormality of embryos and body weight of day-old chicks. Semen quality was not significantly affected by dietary DDGS. Yeast supplementation increased (p≤0.05) sperm concentration per ejaculate by 5.21% and total normal sperm/ejaculate and sperm concentration by 5.87%. Increasing DDGS levels up to 10% and 20% decreased blood plasma total cholesterol by about 4.1%. Enzyme cocktail supplementation increased (p≤0.05) blood plasma Ca by 5.4% of 20% DDGS diets, but other blood plasma parameters were unaffected. Enzyme cocktail addition to DDGS diets also decreased plasma cholesterol by 3.63%. Feeding a 10% and 20% DDGS diet increased (p≤0.05) plasma creatinine by 9.75% and decreased the uric acid/creatinine ratio by about 11.1%. In conclusion, corn DDGS could be included in dual-purpose breeding hen’s diet up to 20% without adverse effects on the sustainability of the quality of eggs and semen, fertility and hatchability, and blood biochemistry. Furthermore, enzyme cocktail at 500 gm/ton feed and yeast at 1 kg/ton feed supplementations significantly and similarly improved eggshell thickness by 1.44-1.72%, and yeast increased sperm concentration and total sperm output per ejaculate. Key words: Distillers dried grains with soluble; Breeding hens; Multi-enzymes; Yeast; Fertility; Hatchability; Semen quality.

The Influence of Trait Preferences and Breeding Practices on Local Chicken Genetic Resource Conservation in Igunga District, Tanzania

A cross-sectional study was conducted to determine the influence of farmers’ trait preferences and breeding practices on local chicken genetic resource conservation in Igunga District, Tabora Region of Tanzania. The study used proportionate random sampling to obtain 384 respondents in ten study villages within two wards. Data were collected through a household survey, key informant interviews (n=5), and focus group discussions (n=10). Descriptive statistics such as mean, percentage and frequencies are used to present the findings. Chi-square establishes the association between variables. The relative importance indices (RII) model determines the level of importance of preferred local chicken traits. The findings indicates that natural mating and slaughter of the chickens with undesirable characteristics as main breeding methods and are statistically significant in between the two wards (p<0.05). Furthermore, findings show that Kuchi is the most preferred local chicken ecotype due to its large body weight and size. Findings on RII on breeding hen indicates that hen egg number with RII=0.9 as the most preferred trait (first rank) followed by hatchability with RII=0.87 (second rank) and mothering behavior with RII =0.86 (third rank). Furthermore, the cock body size ranks first with RII=0.9 followed by cock weight as a second rank with RII = 0.86 and cock disease resistance which ranks third with RII=0.85. Government officials affirm that local chickens are more resilient to diseases than other breeds. The local chicken traders contend that the market value of the local chickens depends on large body weight or frame and plumage color whereas farmers confirm that the preferred breed and traits is focused on economic motives. The study suggests that characterization of local chickens is an important step prior to setting strategies for breeding, utilization and conservation of the resources.

Production system and breeding practice of indigenous chickens in selected districts of Dawro zone and Konta special district, Southern Ethiopia

Abstract. Melak A, Kenfo H, Aseged T, Hailu A. 2021. Production system and breeding practice of indigenous chickens in selected districts of Dawro zone and Konta special district, Southern Ethiopia. Asian J Agric 5: 72-83. This study was conducted to understand the production system, breeding practices, selection criteria, and production constraints of chickens to have a baseline for future production strategies in the study area. The data was collected through individual interviews, focus group discussions, and personal observations. A semi-structured questionnaire using Food and Agriculture Organization Guidelines was used to avail the views of the respondents. Based on chicken population, production potential, and road accessibility, a total of 90 households from six kebeles were considered for an individual interview. The data was analyzed using SPSS software version 23.0 and an index was calculated for all ranked variables like the importance of livestock, purpose of keeping chicken, selection criteria, culling criteria, and constraints of chicken production. The index value of meat production and income generation in midland agroecology were 0.28 and 0.26 respectively. Also, the index value of income generation and meat production in lowland agroecology were 0.31 and 0.25 respectively. It is concluded that both female and male chickens are maintained mainly for income generation followed by meat sources. A variable that was given a higher priority in breeding selection was body size and health conditions, for male and female chickens respectively. Most of the respondents select their breeding hen in health, egg production, and age with an index value of 0.44 and 0.36 and 0.15 respectively; while their breeding cock in body size, disease resistance, and color with an index value of 0.36, 0.29, and 0.28 respectively. Disease and predators were the major constraints of chicken production mentioned in the study area. Therefore, addressing these constraints is important to design a successful genetic improvement scheme.

Expert knowledge assessment of threats and conservation strategies for breeding Hen Harrier and Short-eared Owl across Europe

SummaryHen Harrier Circus cyaneus and Short-eared Owl Asio flammeus are open-country birds of prey with overlapping distributions. Although both species face similar conservation threats across their ranges, work to date has largely been undertaken at a national scale with few attempts to collate and assess factors relevant to their conservation at an international scale. Here we use an expert knowledge approach to evaluate the impact of conservation threats and the effectiveness of conservation strategies for each species across Europe. We report results of responses to a questionnaire from 23 Hen Harrier experts from nine countries and 12 Short-eared Owl experts from six countries. The majority of responses for both species reported declines in breeding numbers. The perceived impact of threats was broadly similar for both species: ecological factors (predation, extreme weather and prey availability), changes in land use (habitat loss and agricultural intensification) and indirect persecution (accidental nest destruction) were considered to be the greatest threats to breeding Hen Harrier and Short-eared Owl. Short-eared Owl experts also highlighted lack of knowledge and difficulties associated with monitoring as a major conservation challenge. Despite broad-scale similarities, geographical variation was also apparent in the perceived importance of conservation threats, with some threats (such as direct persecution, large-scale afforestation or habitat degradation) requiring country-specific actions. Implementation of different conservation strategies also varied between countries, with the designation of protected areas reported as the most widespread conservation strategy adopted, followed by species and habitat management. However, protected areas (including species-specific protected areas) were perceived to be less effective than active management of species and habitats. These findings highlight the overlap between the conservation requirements of these two species, and the need for collaborative international research and conservation approaches that prioritise pro-active conservation strategies subject to continued assessment and with specific conservation goals.

Village Chicken Breeding Objectives and Trait Preferences of Chicken Producers’ in Western Amhara, Ethiopia

This study was carried out to generate base line information on village chicken production objective, breeding practice and trait preference of chicken producers in South Achefre, Banija and FagitaLekoma districts of western Amhara. Multi stage sampling procedures were employed to select the study villages and respondents, where nine villages and 180 respondents were selected by purposive and random sampling techniques, respectively. Data were collected by individual survey using Open Data Kit. The collected data were analyzed using descriptive statistics of SPSS version 20 and ranking index. Main purposes of keeping chicken in the study area are sale of egg and live adult chicken and farmers have a multiple breeding practice. Exotic breed was the first priority of chicken producers. The three most preferred trait for the selection of breeding hen are egg production trait, disease resistance and mothering ability, while the three most preferred trait for the selection of breeding cockare body conformation/ physical appearance, body size and diseases resistance. Comprehensible knowledge on breeding practices, objectives and trait preferences of chicken owners are crucial for development of holistic and applicable genetic improvement program. Hence, production objectives and trait preference should incorporate in designing genetic improvement breeding programs to assure sustainable utilization and improvement of indigenous chickens. Keywords: Breeding hen, Breeding practices, Breeding objectives, Trait preference DOI: 10.7176/JBAH/10-9-03 Publication date: May 31 st 2020

Anthropogenic pressures within the breeding range of the Hen Harrier Circus cyaneus in Ireland

ABSTRACTCapsulePatterns in the frequency and co-occurrence of anthropogenic pressures associated with suitable breeding habitat for Hen Harriers Circus cyaneus demonstrates the need for specific, focussed management and policy options aimed at mitigating impacts on this threatened population.AimsTo describe anthropogenic pressures and threats in the upland breeding range of Hen Harriers and to explore their potential impacts on the declining Hen Harrier population.MethodsWe used text mining, mixed-effects models, principal component analysis and clustering methods to explore anthropogenic pressures on suitable breeding and foraging habitats for Hen Harriers in Ireland, based on the 2015 national breeding Hen Harrier survey data.ResultsMixed-effects models described a strong influence of agriculture, forestry, predator activity, and recreational activities on survey areas that contained Hen Harrier territories. Cluster analyses described three discrete pressure clusters and showed consistent co-occurrence of independent pressures.ConclusionsAreas of suitable habitat for Hen Harriers in the uplands overlap with areas that experience anthropogenic pressures known to negatively impact on this vulnerable bird species. Combined with clear evidence for the co-occurrence of multiple pressures at a regional scale, this demonstrates a clear need for statutory agencies to consider the potential cumulative impacts of individual pressures when developing conservation strategies for Hen Harriers.

Ammonia and greenhouse gas emissions following the application of clinoptilolite on the litter of a breeding hen house.

The husbandry of chicken for meat generates high levels of gases, being a serious problem for the health of birds and workers as well as for the environment. The aim of the present study was to assess the effect of clinoptilolite as litter additive on the concentrations and emissions of ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) from a breeding hen house under Mediterranean climate conditions. Two similar breeding hen houses were selected, and one house was assigned as control whereas the other house was treated with clinoptilolite as a litter additive. Data were collected during the winter season, in two occasions, first between 26 November and 18 December 2017 and second from 1 to 20 February 2018. Results showed that the application of clinoptilolite on the litter of a breeding hen house reduces the NH3 and N2O losses in 28 and 34%, respectively, but appears to have no effect on CO2 losses. In addition, the in-house CH4 concentrations were below the detection limits.

Ammonia, Nitrous Oxide, Carbon Dioxide and Methane Emissions from Commercial Broiler Houses in Mediterranean Portugal

Limited data are available on ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) emissions from poultry housing in Mediterranean countries. The aim of the present study was to assess the NH3, N2O, CO2 and CH4 emission rates from commercial breeding hen and broiler houses under Mediterranean climate conditions. Research was conducted at one commercial breeding hen house and in two commercial broiler houses located in central Portugal. The environmental conditions, gas concentrations and ventilation rates were measured in the cold (8.0 ± 2.1 °C) and hot (20.7 ± 1.9 °C) season for the breeding hen house, whereas for the two broiler houses, measurements were made during one fattening cycle in the fall (17.3 ± 1.7 °C) season. Results showed that the annual average emission rates for breeding hen and broiler houses were 0.52 ± 0.27 and 0.06 ± 0.01 for NH3, 0.030 ± 0.042 and 0.006 ± 0.001 for N2O, 169.6 ± 56.2 and 58.0 ± 15.1 for CO2 and 0.092 ± 0.131 and 0.0113 ± 0.0002 g day−1 bird−1 for CH4, respectively. The N2O emission rates observed in breeding hen houses may have been overestimated, being higher than previously reported for Mediterranean countries.

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2016

ABSTRACTCapsule: The fifth UK and the Isle of Man survey of Hen Harrier in 2016 showed varying trends by country and region.Aim: To estimate the size of the breeding Hen Harrier population (with associated 95% confidence intervals) in the UK and Isle of Man, constituent countries and Scottish regions, in 2016 and calculate population change over the five surveys to date.Methods: Complete surveys were made of all 10-km squares likely to be occupied by breeding Hen Harriers in England, Wales, Northern Ireland and the Isle of Man, using standard methods developed for previous national surveys. In Scotland, self-selected 10-km squares were surveyed by volunteers and a stratified random selection of the remaining 10-km squares within the known breeding range was surveyed.Results: The UK and Isle of Man Hen Harrier population was estimated at 575 territorial pairs (95% confidence limits, 477–694), a non-significant decline of 13% since 2010 but a significant decline of 24% since 2004. Scotland held the majority (80%) of the population with 460 (359–573) territorial pairs. Elsewhere, 46 territorial pairs were recorded in Northern Ireland, 35 in Wales, 30 in the Isle of Man and four in England. Significant decreases were recorded in the number of pairs in Scotland using grouse moor (−57%) and young forest (−54%).Conclusion: The combined breeding population of Hen Harriers in the UK and Isle of Man has shown a non-significant decline between 2010 and 2016. There were notable decreases in England, Northern Ireland and Wales since 2010.

Hen Harrier Circus cyaneus population trends in relation to wind farms

ABSTRACTCapsule: The data presented here demonstrate a considerable spatial overlap between wind farms and the breeding distribution of Hen Harriers in Ireland, but evidence for a negative impact of wind farms on their population is weak.Aims: To assess the extent of the overlap between wind farms and breeding Hen Harriers and to investigate their potential impact on Hen Harrier population trends.Methods: Data on Hen Harrier breeding distribution in 10 km × 10 km survey squares from national surveys were used in conjunction with information on the location of wind farms to examine whether, and to what extent, changes in Hen Harrier distribution and abundance between 2000 and 2010 were related to wind energy development.Results: Of the 69 survey squares holding Hen Harriers during the 2010 breeding season, 28% also overlapped with one or more wind farms. Data from 36 of the squares with breeding Hen Harriers during the 2000 survey revealed a marginally non-significant negative relationship between wind farm presence and change in the number of breeding pairs between 2000 and 2010.Conclusions: A considerable overlap exists between Hen Harrier breeding distribution and the location of wind farms in Ireland, particularly in areas between 200 and 400 m above sea level. The presence of wind farms is negatively related to Hen Harrier population trends in squares surveyed in 2000 and 2010, but this relationship is not statistically significant, and may not be causal. This is the first study to assess the influence of wind energy development on Hen Harriers at such a large geographic and population scale.

The status of the Hen Harrier, Circus cyaneus, in the UK and Isle of Man in 2010

Capsule The fourth national survey of Hen Harrier showed that the population in the UK and the Isle of Man declined significantly between 2004 and 2010.Aim To estimate the size of the breeding Hen Harrier population (with associated 95% confidence intervals) in the UK and Isle of Man, constituent countries and Scottish regions, in 2010 and calculate population change since previous surveys in 1998 and 2004.Methods Complete surveys were made of 10-km squares likely to be occupied by breeding Hen Harriers in England, Wales, Northern Ireland and the Isle of Man, using standard methods developed for previous national surveys. In Scotland, a ‘census’ area was non-randomly selected for survey by volunteers, and randomly selected squares were surveyed in two strata covering the rest of the known range.Results The UK and Isle of Man Hen Harrier population was estimated at 662 territorial pairs (95% confidence interval (CI): 576–770), a significant decline of 18% since 2004. Scotland holds the bulk (76%) of the population (505 territorial pairs; 95% CI: 417–612), with smaller numbers in Northern Ireland (59 pairs), Wales (57 pairs), the Isle of Man (29 pairs) and England (12 pairs). Declines of 49% and 20% were observed in the Isle of Man and in Scotland, respectively, whereas the Welsh population increased by 33%. A significant decrease was recorded in numbers of pairs using young and mature plantation forest in Scotland.Conclusion The breeding population of Hen Harriers in the UK and Isle of Man declined between 2004 and 2010. Notable decreases in Scotland and the Isle of Man may be related to habitat change and illegal persecution. Illegal persecution continues to limit the population size of harriers in England to very low levels.

METHIONINE AND SELENIUM YEAST SUPPLEMENTATIONS OF THE HEN DIETS AFFECT ANTIOXIDANT AND GEL PROPERTIES IN THE CHICK MYOFIBRILLAR PROTEIN

ABSTRACT The effects of supplementing Langshan breeding hen diets with selenium (Se) and methionine (Met) on antioxidant and gel properties in the chick myofibrillar protein were assessed. Four hundred and fifty hens were randomly divided into nine treatments with five replicates each treatment and fed 1 of 9 corn soybean diets with 0, 0.30 and 0.60 mg Se/kg from Se‐yeast and 3.2, 4.0 and 5.4 g Met/kg from DL‐methionine, respectively. After incubation, 250 chickens each treatment were randomly divided into five replicates and fed the same diet. At 21 days old, two male chicks each replicate were slaughtered. The Met and Se supplementations of the hen diets increased the muscle tissue Se content and decreased disulfide bond and protein carbonyl contents in the muscle. The higher levels of Met and Se (5.4 g/kg Met and 0.60 mg/kg Se) significantly increased reactive sulfhydryl content in the muscle. The intermediate levels of Met and Se (4.0 g/kg Met and 0.30 mg/kg Se) significantly increased gel hardness and water‐holding capacity of the gel and the higher levels of Met and Se (5.4 g/kg Met and 0.60 mg/kg Se) decreased gel hardness and water‐holding capacity of the gel to an extent. The conclusion was drawn that 0.30 mg/kg Se and 4.0 mg/kg Met supplementations of the hen diets could improve the protein gel and antioxidant properties in the chick to an extent. PRACTICAL APPLICATIONSProtein oxidation is detrimental to meat quality. Nowadays, the most obvious strategy is that various antioxidants have been used to meat products. However, various mechanisms and substances in the body can protect against oxidation. The antioxidant system could be established in advance during the embryonic period, utilizing the micronutrients present in the egg, and ultimately dependent on the hen diet. This appears to have potential in the meat industry once it is proved to be feasible.

The importance of pre‐thicket conifer plantations for nesting Hen Harriers Circus cyaneus in Ireland

Hen Harriers Circus cyaneus are threatened across much of their range and their conservation requires appropriate habitat management. The locations of 148 Hen Harrier nests found in the Republic of Ireland during national breeding surveys in 2000 and 2005 were used to assess nest‐site selection. The distribution of these nests was compared to distributions of randomly located points to investigate selection at the scale of the nest‐site and landscape. The main nesting habitats selected were pre‐thicket stage of first and, particularly, second rotation plantations, mostly of exotic conifers. There was no evidence that the area of post‐closure plantations negatively affected Hen Harrier nest distribution. There was a positive correlation across study areas between changes in numbers of Hen Harrier nests between 2000 and 2005 and changes in the area of pre‐thicket second rotation plantations over the same period. The overall effect of plantation forests on breeding Hen Harriers in Ireland therefore appears to be positive. However, this study did not consider the effects of plantation habitats on breeding success. Improved grassland was strongly avoided as a nesting habitat. Furthermore, after controlling for the influence of nesting habitat on nest location, landscapes with a high percentage cover of improved grassland were also avoided. Further agricultural intensification of grassland in areas where Hen Harriers breed is likely to have a negative impact on this species. These results are required for the development of management strategies for the conservation of this species.

The Presence of Arcobacter Species in Breeding Hens and Eggs from These Hens

The presence of Arcobacter spp. in 2 breeding hen flocks was determined by examination of the intestinal tract, oviduct magnum mucosa, and ovarian follicles of slaughtered chicken. The bacteria were detected by PCR and cultural isolation in 34 out of 40 intestinal tracts from one flock (A) and 6 out of 30 from the other (B). The strains were Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii. From flock A, arcobacters were recovered from 6 out of 40 oviduct magnum mucosa samples. The majority of isolated strains were A. butzleri. Arcobacter spp. could not be detected, by either PCR or isolation, from 20 eggs collected on the farm of flock A and from 20 eggs still remaining in the vagina of hens in flock B. Furthermore, none of the ovarian follicles from each flock were positive. The results indicate that breeding hens can be infected with Arcobacter spp. in the intestinal tract and oviduct. No evidence was obtained for transmission of Arcobacter spp. from hens to eggs.

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2004, and a comparison with the 1988/89 and 1998 surveys

Capsule The population of breeding Hen Harriers in the UK and Isle of Man increased between 1998 and 2004, although country and regional trends differed. Aims To estimate the size of the UK and Isle of Man Hen Harrier breeding population in 2004, and to compare this with previous estimates made in 1988/89 and 1998. Methods Surveys were carried out in core and a stratified random sample of 10-km squares throughout the known range, using the same methods as in the 1988/89 and 1998 national surveys. Results There were an estimated 806 territorial pairs in the UK and Isle of Man in 2004, a significant 41% increase from the 1998 estimate of 570 pairs. Increases were found throughout, with the exception of south and east Scotland and England, where numbers decreased. Scotland held 79% of the UK and Isle of Man breeding population in 2004, and 10% of Scottish pairs were associated with non-moorland habitats, such as mature conifer plantations and scrub/brash. Conclusions There was a substantial increase in the breeding population in most regions of the UK and Isle of Man between 1998 and 2004, possibly aided by increased use of non-moorland habitats. However, populations declined in upland areas of southern and eastern Scotland and northern England. Continuing illegal persecution arising from perceived conflicts between breeding Hen Harriers and driven grouse shooting may be a major cause of these regional declines.

Status of the Hen Harrier Circus cyaneus in the UK and the Isle of Man in 1998

A survey of breeding Hen Harriers in the UK and the Isle of Man carried out in 1998 consisted of two parts: a complete census of 10-km squares at the core of the species'known range, and a random sample of 10-km squares across the rest of its known recent range. From this, the UK and Isle of Man breeding population was estimated at 570 territorial pairs: 436 in Scotland, 19 in England, 28 in Wales, 38 in Northern Ireland and 49 on the Isle of Man. Although there was no overall change in the size of the UK and Isle of Man population between 1988–94 and 1998, numbers declined in Orkney and increased in Northern Ireland. In Scotland, numbers increased on grouse moors and decreased in young plantation between 1988–89 and 1998, so that 55% of the population is now found on grouse moor. A similar situation exists in England, but in Northern Ireland 45% of the population was found breeding in open areas within mature conifer plantations in 1998.

Sensitivity of willow grouse Lagopus lagopus population dynamics to variations in demographic parameters

In order to estimate the potential importance of each of the demographic traits egg, chick, and apparent winter survival on willow grouse Lagopus lagopus population dynamics, a sensitivity/elasticity analysis on a general model for the growth rate of breeding hen willow grouse numbers was performed. The demographic parameters used were taken from a 21‐year study of willow grouse population dynamics on a Norwegian island. The growth rate of breeding hen numbers may be sensitive to changes in a parameter either because of the structure of the model or because of a substantial between year variation in the parameter. Therefore, three measures of parameter importance were used: sensitivity, elasticity and an actual elasticity coefficient (AE‐coefficient). Sensitivity is an unsealed measure of the impact of a parameter, and thus cannot be used for comparisons between different parameters. Elasticity is a scaled measure of sensitivity allowing direct comparison between effects of different parameters on the growth rate (λ). To interpret the true effect of a demographic parameter on λ, between year variations in the parameter must be accounted for. The actual elasticity coefficient of each parameter is the product of the elasticity coefficient and the coefficient of variation, CV, for the demographic parameter in question. Sensitivity, elasticity and AE‐coefficients showed that apparent winter survival of juveniles had the largest potential impact on changes in X, followed by egg survival, chick survival and adult apparent winter survival. Considering elasticity coefficients alone, apparent winter survival compared to survival from egg laying to four weeks after hatching had 2.3 times the impact on X. However, between year variation in apparent winter survival was far less than between year variation in survival from egg laying to four weeks after hatching, which leads to them both having a similar impact on X. Management efforts on willow grouse have largely been devoted to enhancing survival from egg laying to four weeks after hatching which was believed to be the single most important factor determining population size. The results presented suggest that equal attention should be paid to winter survival. One cause of reduced winter survival may be hunting. A model incorporating the area specific survival and chick production resulted in λ= 1, when chick production was 1.8 chicks per adult and when there was no hunting. The model suggested that grouse could not be hunted in four of the 21 years without reducing the population size on the island and in many years only a modest harvest could be recommended.

Effects of dietary borate and aluminate on riboflavin metabolism in the breeding hen

Breeding hens were used to investigate the effects of aluminate and borate ingestion on riboflavin metabolism. Groups of six hens were fed on either a control diet, or the control diet plus 15 g kg-1 of either sodium metaborate or sodium meta-aluminate. All diets contained 6 mg kg-1 riboflavin. Daily egg production per hen in the borate group had mean values of 0.71, 0.21 and 0.02 for the three weeks of the study. The values were 0.91, 0.91, 0.86 and 0.86, 0.74, 0.89 for the control and aluminate groups, respectively. Fertility (fertile eggs per 100 set) and hatchability (live chicks per 100 fertile eggs) were both nil in the borate-treated hens, compared with 57 and 95 and 59 and 100 for the control and aluminate-treated hens, respectively. Fluorimetric analysis of blood plasma, egg yolk and albumen showed that the riboflavin contents of all tissues were greatly reduced in the borate-treated hens. Borate ingestion can therefore induce a severe riboflavin deficiency in the hen, but aluminium, a more universal contaminant of food or water, did not impair riboflavin metabolism when fed as aluminate.