Caged Layers Research Articles

Claw Abrasives in Layer Cages - A Review

A review was undertaken to obtain information on the range of claw abrasives which could be used in layer cages to keep claws of hens blunt. In Europe a council directive has been issued which requires that all layer cages be fitted with suitable claw shortening devices. Research in Europe on claw abrasives suggest that abrasives reduce claw length of hens, improves feather cover, lowers mortality and reduces the incidence of scratches and entrapment injuries. More recent trials in Australia showed that claw abrasives could result in mortality in hens from prolapse and cannibalism. A low-cost, non-invasive method by which the claws of caged layers can be kept short and blunt can be achieved by fitting 8 mm strips of abrasive tape on the egg guard. Bird's claws scrape against this tape while they are feeding. In Australia studies have shown that abrasive paint was more effective and more durable as a claw shortener than abrasive strips. The birds using the abrasive paint had the shortest claw length and lowest claw sharpness. Other work in Europe has shown that strips of sand fixed on the egg baffle with resin had a significant abrasive effect on the nails but by the end of the laying period large parts of the strip had been worn down. Claw shorteners have also been produced during cage manufacture by pressing a tread to make a perforated baffle. One of the most durable claw abrasives is a metal plate with abrasive iron filings. Other durable abrasives such as stone are also being tested for suitability as a claw abrasive.

Mechanical barrier for preventing climbing by lesser mealworm (Coleoptera: Tenebrionidae) and hide beetle (Coleoptera: Dermestidae) larvae in poultry houses.

Mechanical barriers consisting of bands of polyethylene terepthalate resin attached to wooden posts by latex caulk adhesive and staples were 100% effective in preventing passage of dispersing lesser mealworm, Alphitobius diaperinus (Panzer), larvae in the laboratory. Barriers continued to be 100% effective after beinig held in a caged layer poultry house for 3 mo. Polyethylene terepthalate barriers installed on support posts in a pullet house in Brooker, FL, were >92% effective against natural populations of lesser mealworm larvae 6 mo after installation. The barriers also were >94% effective against natural populations of larvae of the hide beetle, Dermestes maculatus DeGeer, when fly populations were low. Fecal spot depositions by house flies in excess of 31 cumulative fly spots per square centimeter on spot cards reduced the effectiveness of the barriers to 79-90%, and barrier efficacy was reduced to 40-56% when fly spots covered >80% of the surface of the plastic. Washing the barriers with water to remove fly spots restored their effectiveness against hide beetle larvae to >99%.

Environmental enrichment for poultry welfare

AbstractEnvironmental enrichment can significantly improve poultry welfare, productivity and profitability by reducing the expression of harmful behaviours, like fear or feather pecking. However, some studies have yielded inconsistent results and many so-called enrichment stimuli elicited little or no interest. This probably reflected the wide array of stimuli used and the paucity of thought given to what a chicken (Gallus gallus domesticus) might find enriching. Clearly, the design of enrichment devices required more critical thought. Our immediate objectives were to establish chickens' specific preferences and thereby guide the development of practical enrichment strategies. First, we established that chicks showed increased use of an environment when it was enriched with simple, manipulable objects. Our use of video playback to assess chickens' responses to specific attributes of selected images then revealed that visual enrichment stimuli should incorporate movement, brightness, colour, and moderate complexity. Next, a survey revealed that almost 50% of the farmers who replied routinely played the radio to their flocks and that the perceived benefits included reduced aggression, improved health and increased productivity. Finally, we showed that a simple device consisting of a bunch of white strings is an extremely attractive pecking stimulus for chicks and adults of various strains of laying hens. Rather than rapidly losing interest in the devices the birds pecked progressively more at them with repeated exposure in short-term experiments. Furthermore, they were still being pecked at 17 and 2 weeks after their incorporation in the home pens of groups of 1-day-old chicks and adult hens, respectively. Even more encouragingly, the provision of string reduced feather pecking in birds of an experimental line showing high levels of this behavioural vice. It also reduced feather damage in caged layers at a commercial farm. The provision of string devices increases the opportunity for the birds to engage in behaviours that are fundamental to their nature, such as exploration and foraging. By maintaining lengthy interest and apparently reducing the expression of damaging feather pecking, string devices also satisfy other critical requirements of effective environmental enrichment. They have the added advantages of low cost, ready availability, ease of installation, and durability.Collectively, these findings strongly support the hypotheses that extraneous stimulation is important to chickens and that the provision of appropriate visual, auditory and tactile enrichment stimuli can improve their welfare. Projecting images onto the walls of a poultry house could perhaps provide an additional source of visual stimulation, but this requires further investigation. Playing the radio was not only beneficial in terms of welfare and performance but it is probably one of the easiest and most practicable ways of enriching the environment for the birds and the stockpersons. The routine incorporation of string devices in rearing and laying cages is also considered likely to reduce boredom and feather pecking and thereby improve the birds' welfare and productivity. In conclusion, I wholeheartedly recommend the integrated application of string pecking devices and auditory enrichment.

The Influence of Bulking Material Type and Volume On In-house Composting in High-Rise, Caged Layer Facilities

In-house composting involves treating manure where it accumulates on the floor of high-rise, caged layer facilities. This process produces a partially composted material and can aid in house fly (Musca domestica L.) control by generating temperatures in the thermophilic range (≥43°C). Two trials were conducted to determine the effect of material volume and the use of previously composted material (starter) or wheat (Triticum aestivum L.) straw as bulking agents on compost temperatures and material properties. In Trial 1, starter combined with wheat straw or wheat straw alone were added to separate quadrants in a layer building, formed into windrows, and turned biweekly. Temperatures were consistently higher with the starter treatment, but both treatments followed a distinct pattern where temperatures peaked on the day of turning and declined rapidly thereafter. The starter treatment had higher initial volume (0.19 m3 m−1 row) than straw alone (0.13 m3 m−1 row), and maintained proportionately higher volumes throughout the trial. Volume in both treatments increased linearly with time and was correlated with peak compost temperature on the day of turning. Regression analysis indicated that a critical volume of 0.18 m3 m−1 row was required to consistently achieve compost temperatures ≥43°C. In a second trial, starter alone was compared to wheat straw at two rates. Volumes for all treatments initially ranged from 0.20 to 0.28 m3 m−1 row and increased linearly throughout the trial. Temperatures consistently exceeded 43°C on the day of turning. Analysis of the materials from both trials indicated that starter or straw had little effect on %moisture, %carbon, %nitrogen, or carbon:nitrogen ratio of composting materials beyond the first week after windrow establishment. These results indicate that material volume is more important than the use of starter or straw materials as bulking agents to achieve in-house composting temperatures ≥ 43°C.

Bactericidal Effects of Negative Air Ions on Airborne and Surface Salmonella Enteritidis from an Artificially Generated Aerosol

The bactericidal effect of high levels of negative ions was studied using a custom-built electrostatic space charge device. To investigate whether the ion-enriched air exerted a bactericidal effect, an aerosol containing Salmonella Enteritidis (SE) was pumped into a sealed plastic chamber. Plates of XLT4 agar were attached to the walls, top, and bottom of the chamber and exposed to the aerosol for 3 h with and without the ionizer treatment. The plates were then removed from the chamber, incubated at 37°C for 24 h, and colonies were counted. An average of greater than 103 CFU/plate were observed on plates exposed to the aerosol without the ionizer treatment (control) compared with an average of less than 53 CFU/plate on the ionizer-treated plates. In another series of experiments, the SE aerosol was pumped for 3 h into an empty chamber containing only the ionizer and allowed to collect on the internal surfaces. The inside surfaces of the chamber were then rinsed with 100 ml phosphate-buffered saline that was then plated onto XLT4 plates. While the rinse from the control chamber contained colony counts greater than 400 CFU/ml of wash, no colonies were found in the rinse from the ionizer-treatment chamber. These results indicate that high levels of negative air ions can have a significant impact on the airborne microbial load, and that most of this effect is through direct killing of the organisms. This technology, which also causes significant reduction in airborne dust, has already been successfully applied for poultry hatching cabinets and caged layer rooms. Other potential applications include any enclosed space such as food processing areas, medical institutions, the workplace, and the home, where reduction of airborne and surface pathogens is desired.

Effects of Whole Crop Corn Ensiled With Cage Layer Manure on Nutritional Quality and Microbial Protein Synthesis in Sheep

Effects of Whole Crop Corn Ensiled With Cage Layer Manure on Nutritional Quality and Microbial Protein Synthesis in Sheep

ARMCANZ discussions the future of layer cages

Australian Veterinary JournalVolume 78, Issue 11 p. 739-739 ARMCANZ discussions the future of layer cages First published: 10 March 2008 https://doi.org/10.1111/j.1751-0813.2000.tb10432.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume78, Issue11November 2000Pages 739-739 RelatedInformation

Reducing Dust in a Caged Layer Room: An Electrostatic Space Charge System

Dust has been shown to be an important mechanism for airborne transmission of disease-causing agents. Although there are a variety of treatments that can reduce airborne dust, most of them are not practical in areas such as caged layer rooms where dust levels can be relatively high. In this study, an electrostatic space charge system was shown to be very effective on both artificial and naturally generated dust in a caged layer room. Duplicated trials of the system showed a reduction in average concentration of artificially generated dust ranging from 72 to 91% by ionizer treatment - depending on the initial concentration. The treatment reduced concentration of naturally generated dust from mature White Leghorn chickens in cages by an average of 52%. These results show that use of an electrostatic space charge system can significantly reduce dust in caged layer areas, resulting in a lower potential for respiratory problems of workers as well as chickens in these areas.

Osteoporosis in Cage Layers

Osteoporosis in laying hens is a condition that involves the progressive loss of structural bone during the laying period. This bone loss results in increased bone fragility and susceptibility to fracture, with fracture incidences of up to 30% over the laying period and depopulation not uncommon under commercial conditions. A major cause of osteoporosis is the switch in bone formation from structural to medullary bone at the onset of sexual maturity, but structural bone loss is accelerated by the relative inactivity of-caged birds. Allowing birds more exercise, as in aviary systems, results in better bone quality but may not decrease the overall fracture incidence. Good nutrition can help to minimize osteoporosis but is unable to prevent it. Best nutritional practice involves transferring birds to a higher calcium diet at lighting up rather than at first egg, providing a source of calcium in particulate form, and not withdrawing feed some days before depopulation. Breeding may be an effective way of combating ostoporosis. Some bone strength traits have been shown to be heritable, and divergent selection for resistance or susceptibility to osteoporosis has resulted in lines with markedly different bone characteristics. After three generations of selection, the lines differ by 19% for keel bone mineral density, 13% for humerus breaking strength, and 25% for tibia breaking strength and show a sixfold difference in fracture incidence under commercial breeding conditions. The difference in bone quality among the lines is maintained under different housing systems.

Factors Regulating Bone Maturity and Strength in Poultry

Adolescent meat-type poultry and cage layers exhibit a high incidence of bone problems that include bone weakness, deformity, breakage, and infection and osteoporosis-related mortalities. These problems include economic and welfare issues. To improve bone quality in poultry, it is essential to understand the physiological basis of bone maturity and strength in poultry. A complex array of factors that include structural, architectural, compositional, physiological, and nutritional factors interactively determine bone quality and strength. Bone is approximately 70% mineral, 20% organic, and 10% water. Collagen is the major organic matrix that confers tensile strength to the bone, whereas hydroxyapatite provides compressional strength. In recent years, the roles of different collagen crosslinks have been shown to be important in the increase of bone mechanical strength. Similarly, age-related glyco-oxidative modifications of collagen have been shown to increase the stiffness of collagen. These posttranslational modifications of matrix can affect bone quality as it would be affected by the changes in the mineralization process. Our studies show that the growth in the tibia continued until 25 wk of age, which correlated with the increase in the content of hydroxylysylpridinoline (HP) and lysylpyridinoline (LP), the collagen crosslinks. The tibia from 5-wk-old chicks were strong but brittle because of low collagen crosslinks and high mineral content. Bone maturity may relate to its crosslink content. Compared to crosslink content, bone density and ash content showed moderate increases during growth. The bones from younger turkeys were more susceptible to corticosteroid-induced stunting of growth, which also resulted in decreased bone strength. This review discusses how different factors can compromise bone strength by reducing growth, altering shape, affecting mineralization, and affecting collagen crosslinking.

A Dynamic Simulation Model of in-situ Composting Of Caged Layer Manure

A dynamic simulation model for in-situ composting of caged layer manure in-house, was developed and implemented on STELLA® modeling environment. The model formulation was based on solids mass balances, water balances and energy balances. The model was validated with the following parameters from pilot studies: temperature profiles, bulk wet weights, dry weights, and moisture contents. Approximately all the simulated values of bulk wet weights, dry weights and moisture contents fell within one standard deviation of the measured values over four different samplings within the year the experiment was conducted. Similarly the simulated cyclic-temperature profiles predicted the measured temperature profiles fairly accurately, except at points immediately after the weighing sessions.

The effects of long-term caging and molt of Single Comb White Leghorn hens on heterophil to lymphocyte ratios, corticosterone and thyroid hormones

Two commercial strains of 18-wk-old Single Comb White Leghorn (SCWL) hens, HyLine W-36 and DeKalb XL, were housed six hens per cage in layer cages at two densities (361 and 482 cm2 per bird) with two replications each per strain and density combination. The high density treatment contained 24 hens per replication, and the low density treatment contained 18 hens per replication. Egg production was measured during the first egg production cycle, a molt (fast) period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Blood samples were obtained from six hens from each replicate in each strain and density combination (total of 48) at 20, 26, 34, 43, 51, 62, 64, and 68 wk of age. In addition, blood samples were obtained in a random order from hens in each cage, and the sequence of sampling was recorded (1 to 6). Blood smears were made, from which heterophil to lymphocyte ratios (H:L) were determined. Radioimmunoassays were conducted to determine levels of plasma corticosterone (CS), 3,5,3'-triiodothyronine (T3), and thyroxine (T4). The results indicated that strain did not affect percentage hen-day egg production (%HDP). Strain and cage density did not affect H:L, T3, T4, or CS. However, these parameters were affected by bird age, which was related to the egg production cycle. Plasma CS significantly (P < or = 0.001) increased during peak %HDP at 26 wk and 64 wk during the molt (fast), and H:L significantly (P < or = 0.001) increased during the molt (fast) at 64 wk. The sequence in which blood samples were obtained, from hens within a cage in sampling order, also increased plasma CS. The CS was significantly (P < or = 0.001) elevated in the third, fifth, and sixth hens from which blood samples were drawn. Plasma T3 and T4 changed during the production cycle. The T3 was significantly (P < or = 0.0001) depressed during peak egg production at 26 wk and during the molt (fast) at 64 wk when compared with the other time periods. Plasma T4 was depressed (P < or = 0.0001) at 51 wk and was elevated (P < or = 0.0001) at 64 wk during the molt (fast). The physiological and metabolic parameters of the different hen strains and cage densities were similar during egg production. However, CS, T3, T4, and H:L changed with age in relation to the egg production cycle. In addition, the physiological demands of peak egg production and molt (fast) appeared to be similar.

COOLING LAYING HENS BY INTERMITTENT PARTIAL SURFACE SPRINKLING

This study investigated the efficacy of intermittent partial surface sprinkling to cool caged layers at 20, 38,and 56 weeks of age. Ten birds were used per age group with two birds per paired trial (Experiment, Expt, and Control,Ctrl) that were subjected to an acute heat exposure of 40.0 0.5C air temperature, 45 3% RH, and air velocity of 0.15to 0.20 m/s for a maximum of 8 h. The Expt birds were sprinkled with water mist (8 mL/sprinkling session) on the headand appendages at 15-min intervals from the time when panting was observed; whereas, the Ctrl birds received nosprinkling. Continuous measurement of the rectal temperature and periodic thermographical measurement of the surfacetemperature of the birds were performed. The intermittent partial surface sprinkling had the following merits as comparedwith the control: lower body temperature rise (4.3 vs 5.7C; P < 0.05), higher lethal heat load threshold (10.0 vs 6.6C-h,P < 0.05), longer survival time (145 to > 480 vs 92 to 266 min), and reduced mortality (20 to 60% vs 100%). Themaximum reduction in surface temperature of the head and appendages due to the sprinkling averaged 2.2C. Under thepresent environmental conditions (i.e., 40C, 45% RH, and 0.15 to 0.20 m/s), sprinkling once every 5 to 6 min wouldprovide adequate cooling to prevent the surface temperature from rising. The concept of body heat load ( ) seems toprovide an effective measurement of heat tolerance of the birds under different cooling schemes.

Use of Negative Air Ionization for Reducing Airborne Levels of Salmonella enterica serovar enteritidis in a Room Containing Infected Caged Layers

Removal of Salmonella Enterica serovar enteritidis (S. enteritidis) circulating in the air can be important in reducing S. enteritidis problems in a flock. One potential method to aid in this removal is the use of a negative air ionizer. Such a device imparts a negative charge on airborne particles, causing them to be attracted to grounded surfaces, therefore, effectively taking them out of circulation. Two experiments were conducted to determine whether such a device could lower levels of S. enteritidis in a room containing infected caged laying hens. In both experiments, the negative air ionizer effectively decreased the room airborne levels of S. enteritidis compared to levels in a room lacking a device. This improvement was particularly evident in Experiment 2, in which the S. enteritidis reduction brought about by the ionizer averaged 96.5% during the last 6 days of the sampling period. Failure to brush dust off the ionizer every other day resulted in reduced efficiency. These results demonstrate the potential efficacy of negative air ionization in removing poultry bacterial pathogens in a layer room situation.

Crop Impaction Resulting from Feather Ball Formation in Caged Layers

Abnormal behaviors in commercial poultry, including feather pulling and pica, have been known to occur when birds are exposed to an unfamiliar environment. We report here the development of crop impactions resulting from feather ball formation. Twelve specific-pathogen-free (SPF) chickens were placed in one of three cages housed among a commercial layer flock in three different buildings on a farm site. Three weeks after placement, the birds were removed from the cages and given a physical exam. Chickens were thin, and one bird in each of the three caged groups had a palpable mass at the level of the thoracic inlet. At necropsy, a mass was noted in the crop. Upon further dissection, a wet, foul-smelling mass consisting of feathers and feed debris was recovered. Results from our case indicate that unfamiliar surroundings can cause pica in birds. Hence, avian researchers and veterinarians planning to introduce new birds into a flock, i.e., SPF birds, should consider the birds' previous environmental conditions prior to placement because sudden placement in unfamiliar surroundings can result in pica.

Neem (Azadirachta indica) kernel meal in the diet of White Leghorn layers

1. Neem kernel meal (NKM) was incorporated into a standard layer diet at 0, 100, 150 and 200 g/kg, replacing parts of the soyabean meal and deoiled rice bran. Each diet was offered to 18 White Leghorn layers (25 weeks, 50% egg production) in individual cages for a period of 12 weeks. 2. Results indicated significantly lower food intakes (P<0.01), rates of egg production and egg weights in birds fed on the diets with NKM at 150 and 200 g/kg. Fertility and hatchability were also adversely affected by the higher inclusion rates of NKM. 3. Except for lower egg shell weight and shell thickness (P<0.05) in hens fed NKM at 150 and 200 g/kg, the internal egg quality characteristics were comparable in all groups. 4. Feeding NKM beyond 100 g/kg to laying hens significantly (P<0.01) reduced the content of haemoglobin, erythrocyte count, packed cell volume, serum calcium and uric acid concentrations. However, the leucocyte count, plasma glucose concentration and serum glutamate oxaloacetate transaminase activity were unaltered. Serum glutamate pyruvate transaminase activity was significantly (P<0.05) reduced in birds fed NKM at 200 g/kg. 5. Thus NKM at 100 g/kg in a layer diet would appear to be safe and cost-effective.

Effect of dietary calcium and phosphorus concentrations on retention of these nutrients by caged layers

1. A 5 3 factorial experiment was carried out with caged White Leghorn hens with 5 concentrations of calcium (26.0, 29.0, 32.5, 36.0, 39.0 g/kg) and 3 concentrations of phosphorus (4.3, 5.0 and 6.0 g/kg) for 120 d. Variables observed were hen day egg production, food consumption, shell weight, shell weight per unit surface area (SWUSA) and egg content. 2. 36.0 g calcium (Ca) and 4.3 g phosphorus (P) kg were found to be the dietary concentrations that resulted in optimal hen day egg production, shell weight, SWUSA and egg content. 3. Lack of a significant interaction between the effects of calcium and phosphorus on production parameters showed that the dietary Ca: P ratio is not of great importance for the laying hen. 4. Absolute retentions of Ca and P were inversely related to percentage retentions. 5. A balance study of calcium and phosphorus also showed optima at 36.0 g Ca and 4.3 g P per kg. 6. It was inferred that 36.0 g Ca and 5.0 g total P per kg are the optimal concentrations in diets for caged layers in a tropical climate.

Lack of effect of body weight of breeder pullets at various ages and the amount of food allocated on their subsequent laying performance

1. Two factorial experiments were carried out with White Rock (Arbor Acres) female pullets, kept in layer cages, to evaluate the relationship between body weight (BW) at different ages and the amount of food allocated (FA) on laying performance. Differences in BW at the beginning of experiments 1 and 2 (12 and 18 weeks of age, respectively) were obtained by segregating pullets raised under the recommended FA into weight groups (WGs): standard (ST), light BW (LBW) and heavy BW (HBW). Each of the 3 WGs was further divided into 2 subgroups, raised either under the recommended FA or a moderately increased FA until 34 weeks of age. The experiments were terminated at approximately 65 weeks of age. 2. Body weight was significantly (P 0.05) affected by WGs until 28 and 60 weeks, and by FA until 56 and 44 weeks of age in experiments 1 and 2, respectively. The increased FA significantly accelerated the age of onset of egg production and increased BW at that time. Neither of these variables was affected by BW at 12 weeks of age. BW at 18 weeks of age did not affect age of sexual maturity, but at that time the BW of the LBW- and the HBW-birds was significantly lower and higher, respectively, than that of the ST-birds. 3. Number of eggs per laying or per housed hen was not affected by the WG and/or FA. The exception was the significant interaction between the 2 factors in their effect on the number of eggs per laying hen observed in experiment 1, in which the increased FA prevented the decline in the HBW-birds. 4. The data suggest that the laying performance of broiler breeder hens segregated according to their weight at 12 or 18 weeks of age, and kept in layer cages is not affected by their weight at these ages, and thereafter. The effects of a moderate increase in FA, and of the interaction between this factor and WGs, on laying performance, are not straightforward.

Concentrations and Emissions of Airborne Dust in Livestock Buildings in Northern Europe

Field surveys of dust concentrations within and dust emissions from cattle, pig and poultry buildings were conducted in England, the Netherlands, Denmark and Germany. Measurements of inhalable and respirable dust concentrations were made in 329 buildings. Concentrations of CO 2 within and outside the buildings were also measured to estimate ventilation rates for dust emission calculations. Dust concentrations and emissions were a⁄ected significantly by housing type and animal species. Overall mean inhalable and respirable dust concentrations were 0)38 and 0)07 mg/m3 in cattle buildings, 2)19 and 0)23 mg/m3 in pig buildings, and 3)60 and 0)45 mg/m3 in poultry buildings, respectively. Overall mean inhalable and respirable dust emission rates from the buildings were 110 and 19 mg/h bovine, 111 and 14 mg/h pig, and 12 and 2 mg/h bird, respectively. Expressed per 500 kg liveweight, the values become, respectively, 145 and 24 mg/h for cattle; 762 and 85 for pigs; and 3165 and 504 for poultry. Seasonal e⁄ects on dust concentrations in and emissions from cattle buildings were weak. Dust concentrations in pig and poultry buildings were higher in winter than summer. Inhalable dust emission rates from pig and poultry buildings were higher in summer than winter. E⁄ects of season on respirable dust emission rates from pig and poultry buildings were small. Inhalable dust concentrations in cattle buildings were higher in the day than at night, but e⁄ects di⁄ered between countries. Pig buildings showed higher dust (both inhalable and respirable) concentrations in the day than at night. Percheries and buildings for caged layers showed higher inhalable dust concentrations in the day than at night. However, dust concentrations in broiler houses were not a⁄ected by day and night. The high concentrations of inhalable dust in broiler houses, in percheries for hens and in slatted weaner and fattener houses for pigs give cause for concern for both stockman and animal health and performance. ( 1998 Silsoe Research Institute

Effects on white Leghorn hens of constant exposure to ultraviolet light from insect traps

Constant exposure of Hy-Line W-36 White Leghorn hens to ultraviolet light from insect traps resulted in no significant differences in egg production, fertility, hatchability of fertile eggs, or total hatchability. Also, there were no apparent effects on the eyes of the birds. Results were the same when either blacklight or blacklight blue tubes were used. The need for additional testing of light traps for nuisance fly control in commercial caged layer houses is discussed.