Feather Quality Research Articles

Chronic heat stress part 1: Decrease in egg quality, increase in cortisol levels in egg albumen, and reduction in fertility of breeder pekin ducks.

Global warming poses detrimental effects on poultry production leading to substantial economic losses. The goal of our experiment was to test the hypothesis that heat stress (HS) would alter welfare and egg quality (EQ) of breeder ducks. Furthermore, we wanted to test if HS would increase cortisol levels in egg albumen. Adult Pekin ducks were randomly assigned to two different rooms at 85% lay with 60 hens and 20 drakes per room. Baseline data including body weight, body condition scores (BCS), and egg production/quality were collected the week preceding heat treatment. Ducks were subjected to cyclic HS of 35°C for 10h/day and 29.5°C for the remaining 14h/day for 3 weeks while the control room was maintained at 22°C. Eggs were collected daily and analyzed weekly for quality assessment, and for albumen glucocorticoid (GCs) levels using mass spectrometry. One week before the exposure to HS, 10 hens and 5 drakes were euthanized and the same number again after 3weeks and birds necropsied. Data analyses were done by 1- or 2-way ANOVA as appropriate with a Tukey-Kramer post hoc test. BCS were analyzed using a chi-squared test. A p ≤ 0.05 was considered significant. Circulating levels of corticosterone were significantly (p < 0.01) elevated at week 1 only in the HS hens. The circulating levels of cortisol increased significantly at week 1 and 2 (p < 0.05), and week 3 (p < 0.01) in the hens and at weeks 2 and 3 only (p < 0.05) in the drakes. Feather quality scores (p < 0.01), feather cleanliness scores (p < 0.001) and footpad quality scores (p < 0.05) increased significantly in the HS group. HS elicited a significant (p < 0.001) decrease in egg production at weeks 1 and 3. Hens in the HS group showed significantly decreased BW (p < 0.001) and number of follicles (p < 0.05). Shell weight decreased significantly at week 1 only (p < 0.05) compared to controls. Yolk weight decreased significantly at week 3 (p < 0.01) compared to controls. HS elicited a significant increase in albumen cortisol levels at week 1 (p < 0.05) and week 3 (p < 0.05). Thus, cortisol may provide critical information to further understand and to improve welfare.

Feather characteristics of loral zone in an insectivorous passerine: The Iberian gray shrike Lanius meridionalis, in southern France.

In the French Mediterranean plain, the northern extreme of its native range, the Iberian gray shrike, Lanius meridionalis, predominantly feeds on arthropods. Its type of loral plumage plays a key role in protecting its eyes while transporting large prey. The aims are to understand the role played by feathers in protecting the animal from various types of defensive prey. I combine an inspection of large insect prey types found on larders with a review of bird specimens found in museum collections to examine the morphometric characteristics of rictal feathers and culmen. In addition, precision photographs are used to observe the posture of the plumage in natura. Icould identify four categories of protective feathers: clustered bristles, semi-bristles, semi-plumes distributed in the loral area, and semi-plumes above the eyes. My results suggest that the Iberian gray shrike has a complex structure of loral feathers, specific to its foraging activity and prey types. The presence of these rictal bristles is probably a protection against the movements of larger prey items, which might damage loral zone of Lanius meridionalis.

Identity and characteristics of feathers used as lining in Tree Swallow (Tachycineta bicolor) nests in indiana and Ohio

La construcción del nido representa una parte importante de la inversión parental y puede tener un impacto significativo sobre el éxito reproductivo de muchas especies de aves. La golondrina Tachycineta bicolor anida en cavidades secundarias, aceptando fácilmente cajas nido dentro de las que construyen un nido básico con hierbas en forma de taza y revestido con plumas de otras especies de aves. Identificamos y describimos las características de las plumas usadas como material del nido de T. bicolor en 4 hábitats diferentes en Indiana y Ohio. Monitoreamos 41 cajas nido en 2017 y 53 en 2018. Después que los pichones volaron del nido, recolectamos las plumas de los nidos, las contamos, y las caracterizamos por tamaño, color y tipo. Las plumas del contorno, marrones y de longitud media (5–10 cm) fueron significativamente más comunes que cualquier otro tipo de pluma. Comparamos la prevalencia y las características de las plumas entre nidos en diferentes tipos de hábitats, y los resultados mostraron que los nidos cerca de lagos contenían significativamente más plumas que los nidos de los hábitats agrícolas. Identificamos las plumas utilizando técnicas moleculares y comparaciones morfológicas, y encontramos que éstas pertenecían a 26 especies de 19 familias y 11 órdenes: Galliformes, Anseriformes, Columbiformes, Gruiformes, Charadriiformes, Pelecaniformes, Accipitriformes, Strigiformes, Piciformes, Cathartiformes y Passeriformes; incluyendo 20 especies no reportadas previamente dentro de esos órdenes. Esto indica que las plumas utilizadas por T. bicolor para el revestimiento de sus nidos son más diversas que lo reportado previamente. La identidad de las plumas en cada hábitat coincide con las comunidades de aves en esas áreas, sugiriendo que las golondrinas T. bicolor son recolectoras de plumas generalistas, y que el número y las características de las plumas utilizadas como revestimiento del nido dependen de la disponibilidad de plumas cerca del lugar de anidación. Palabras clave: comportamiento de anidación de aves, construcción del nido, hábitat y disponibilidad de plumas, Hirundinidae, identificación de plumas, revestimiento del nido, secuenciación del fragmento del gen del citocromo oxidasa I (COI).

PSXIII-5 Effects of Stocking Density on the Welfare and Immune Responses of Laying Hens Housed in Small Furnished Cages

Abstract To investigate the effects of stocking density on the welfare and immune responses of laying hens housed in furnished cages, 192 Hy-Line Brown hens were housed in small furnished cages and randomly divided into three groups on their 18 weeks old for low-density group (833 cm2 per hen, LD), medium-density group (625 cm2 per hen, MD), and high-density group (500 cm2 per hen, HD). There are eight cages in each stocking density. The welfare of laying hens was assessed at 22, 42 and 72 weeks of age (WOA) for feather quality, foot cleanness, footpad dermatitis, hyperkeratosis and keel bone damage. After the last welfare assessment, venous blood from the wing of the hen was extracted for testing immune indicators of Immunoglobulin Y (Ig Y), Interferon gamma (IFN-γ), Transforming growth factor beta (TGF-β), Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-6 (IL-6), Interleukin-12 (IL-12) by enzyme-linked immunosorbent assay (ELISA). Results showed that feather quality of laying hens from HD group was worse than hens from LD and MD groups at 42 and 62 WOA (P &amp;lt; 0.05). The foot cleanness score of hens from HD group was worse than other two group hens at 62 WOA (P &amp;lt; 0.05), respectively. There was no significant difference between three groups on other welfare indicators (P &amp;gt; 0.05), but the welfare quality of laying hens got worse with the aging of laying hens. Laying hens from LD group had greater concentrations of serum IFN-γ, IL-2, IL-6 compared with hens from MD and HD groups (P &amp;lt; 0.05). There was no significant difference for other immune responses (P &amp;gt; 0.05). These findings suggest that keeping a high stocking density of laying hens could cause feather damage, impact the welfare quality and reduce the immune responses of laying hens housed in small furnished cages.

Breed-specific expression mode of the Wnt signalling pathway is involved in feather follicle morphogenesis between Anser cygnoide and Anser anser

ABSTRACT Feathers are important economic products. Anser cygnoide (AC) is superior in reproduction, growth and feather quality, while Anser anser (AA) has an advantage in feather yield. Understanding the development of feather follicles facilitates deliberate crossbreeding. Here, we compared feather follicles morphogenesis between AC and AA. Feathers and dorsal skin were sampled at multiple embryonic days to investigate feather phenotypes, feather follicle morphology and the expression of hub molecules (FZD4, β-catenin, LEF1, TCF4 and c-Myc) in the Wnt signalling pathway. We found a marked difference in plumage colour between the two breeds. Feather colour in AA has undergone a ‘black dorsum’ stage and cavity formation in AC was earlier. Furthermore, different trends in molecular hub expression helped explain the phenotypical and morphological differences: the upregulated Wnt signals in AC at E12 and/or E15, as well as in AA at E18, were associated with early epidermal placode formation and cavity formation in AC, also, related to the development of the secondary feather follicles and ‘black dorsum’ in AA. Summarily, breed-specific expression patterns of Wnt signalling pathway between AC and AA might participate in the shaping of breed-specific feather follicles morphogenesis and feather phenotypes. This work provides references for feather follicles development in geese.

No apparent trade-off between the quality of nest-grown feathers and time spent in the nest in an aerial insectivore, the Tree Swallow

Abstract Life history theory provides a framework for understanding how trade-offs generate negative trait associations. Among nestling birds, time spent in the nest, risk of predation, and lifespan covary, but some associations are only found within species while others are only observed between species. A recent comparative study suggests that allocation trade-offs may be alleviated by disinvestment in ephemeral traits, such as nest-grown feathers, that are quickly replaced. However, direct resource allocation trade-offs cannot be inferred from interspecific trait associations without complementary intraspecific studies. Here, we asked whether there is evidence for a within-species allocation trade-off between feather quality and time spent in the nest in Tree Swallows (Tachycineta bicolor). Consistent with the idea that ephemeral traits are deprioritized, nest-grown feathers had lower barb density than adult feathers. However, despite substantial variation in fledging age among nestlings, there was no evidence for a negative association between time in the nest and feather quality. Furthermore, accounting for differences in resource availability by considering provisioning rate and a nest predation treatment did not reveal a trade-off that was masked by variation in resources. Our results are most consistent with the idea that the interspecific association between development and feather quality arises from adaptive specialization, rather than from a direct allocation trade-off.

Feather growth and quality across passerines is explained by breeding rather than moulting latitude.

Tropical bird species are characterized by a comparatively slow pace of life, being predictably different from their temperate zone counterparts in their investments in growth, survival and reproduction. In birds, the development of functional plumage is often considered energetically demanding investment, with consequences on individual fitness and survival. However, current knowledge of interspecific variation in feather growth patterns is mostly based on species of the northern temperate zone. We evaluated patterns in tail feather growth rates (FGR) and feather quality (stress-induced fault bar occurrence; FBO), using 1518 individuals of 167 species and 39 passerine families inhabiting Afrotropical and northern temperate zones. We detected a clear difference in feather traits between species breeding in the temperate and tropical zones, with the latter having significantly slower FGR and three times higher FBO. Moreover, trans-Saharan latitudinal migrants resembled temperate zone residents in that they exhibited a comparatively fast FGR and low FBO, despite sharing moulting environments with tropical species. Our results reveal convergent latitudinal shifts in feather growth investments (latitudinal syndrome) across unrelated passerine families and underscore the importance of breeding latitude in determining cross-species variation in key avian life-history traits.

Deletion in KRT75L4 linked to frizzle feather in Xiushui Yellow Chickens.

Bird feathers are the product of interactions between natural and artificial selection. Feather-related traits are important for chicken selection and breeding. Frizzle feather is characterized by the abnormally development of feathers in chickens. In the current study, frizzle feather characteristics were observed in a local breed called Xiushui Yellow Chicken in Jiangxi, China. To determine the molecular mechanisms that underlie frizzle feather in Xiushui Yellow Chicken, four populations of three breeds (Xiushui Yellow Chicken with frizzle feathers, Xiushui Yellow Chicken with normal feathers, Guangfeng White-Ear Yellow Chicken, and Ningdu Yellow Chicken) were selected for whole-genome resequencing. Using a comparative genome strategy and genome-wide association study, a missense mutation (g.5281494A>G) and a 15-bp deletion (g.5285437-5285451delGATGCCGGCAGGACG) in KRT75L4 were identified as candidate mutations associated with frizzle feather in Xiushui Yellow Chicken. Based on genotyping performed in a large Xiushui Yellow Chicken population, the g.5285437-5285451delGATGCCGGCAGGACG mutation in KRT75L4 was confirmed as the putative causative mutation of frizzle feather. These results deepen the understanding of the molecular mechanisms responsible for frizzle feather, as well as facilitating the molecular detection and selection of the feather phenotype in Xiushui Yellow Chickens.

Efficacy and Function of Feathers, Hair, and Glabrous Skin in the Thermoregulation Strategies of Domestic Animals

Simple SummaryAnimals adopt several strategies to regulate their body temperature by promoting heat loss or gain in hot and cold environments, respectively. This mechanism of heat loss or production is performed in thermal windows. A thermal window is a structure where many blood capillaries facilitate thermal exchange in this region. The presence of feathers, hair, or glabrous (hairless) skin and their structural characteristics greatly influence each species’ capacity to maintain thermal comfort. This factor needs to be considered when implementing new monitoring or measuring techniques such as infrared thermography since interpretations may vary due to the presence or absence of these structures. It is essential to recognize the effects of glabrous skin, hair, and feathers on thermoregulation to identify species-specific thermal windows that allow accurate evaluations of the thermal state of domestic animals.The objective of this review is to describe and analyze the effect of feathers, hair, and glabrous (hairless) skin on the thermoregulation of domestic and endotherm animals, especially concerning the uses and scope of infrared thermography (IRT), scientific findings on heat and cold stress, and differences among species of domestic animals. Clinical medicine considers thermoregulation a mechanism that allows animals to adapt to varying thermal environmental conditions, a process in which the presence of feathers, hair, or glabrous skin influences heat loss or heat retention, respectively, under hot and cold environmental conditions. Evaluating body temperature provides vital information on an individual’s physiological state and health status since variations in euthermia maintenance in vertebrates reflect a significant cellular metabolism deviation that needs to be assessed and quantified. IRT is a non-invasive tool for evaluating thermal responses under thermal stress conditions in animals, where the presence or absence of feathers, hair, and glabrous skin can affect readings and the differences detected. Therefore, anatomical regions, the characteristics of feathers, hair, glabrous skin such as structure, length, color, and extension, and strategies for dissipating or retaining heat together constitute a broad area of opportunity for future research into the phenomena of dermal thermoregulation in domestic species.

Microscopic Analysis of the Plumulaceous Feather Characteristics of Cathartiformes and Accipitriformes in North America

ABSTRACT Although variation in microscopic plumulaceous (downy) feather characters is known to be useful in taxonomic identifications of birds, the conserved characters unique to most avian orders remain understudied. We examined plumulaceous feather characters (morphometric and observed pigmentation patterns [qualitative]) within three avian families (Cathartidae, Pandionidae, Accipitridae) occurring in North America that often require taxonomic identification based on incomplete or fragmentary remains. We found significant quantitative differences among these three families for measurements of barbule length, node width, average number of nodes per barbule, and internode length. We observed additional differences in pigmentation patterns and spine distribution at nodes. Differences in pigment patterns and intensity are diagnostic for distinguishing Black Vulture (Coragyps atratus) from Turkey Vulture (Cathartes aura) within Cathartidae. Further observed differences of a higher percentage of spined structures present at node junctions along the length of barbules are diagnostic of Pandionidae. Within Accipitridae, pigmentation patterns and pigment intensity separate Swallow-tailed Kite (Elanoides forficatus) and White-tailed Kite (Elanus leucurus) from all other taxa; and barbule length, together with average nodes per barbule is unique to Northern Harrier (Circus hudsonius) in the families examined in this study. Although significant differences in a combination of microscopic feather characters among species were seldom observed in this study, family level differences were consistently documented. Results support the use of a suite of microscopic characters in combination with macroscopic feather features, geographic distributions, molecular methods, and other circumstantial evidence to aid in the identification of species of birds from feathers.

Feather pecking and foraging uncorrelated – the redirection hypothesis revisited

ABSTRACT 1. Feather pecking (FP) is said to be a redirection of food-related foraging pecks to feathers. The effects of three foraging enrichments on the pecking behaviours of layer pullets in pens and as hens in cages (Gallus gallus domesticus) were studied. 2. Treatments included no added enrichment (Control), addition of a mix of wheat and sorghum grains (Grain), a mix of wheat and sorghum grains with lucerne and oaten chaff (Chaff), and lucerne hay (Hay). In pens, Hay was provided in racks, while Grain and Chaff were scattered on the floor. In cages, all treatments were provided in racks. It was predicted that enrichments that encouraged more pecking activity would be most successful at reducing FP. 3. Overall pecking activity was similar between all treatments. The Chaff groups tended to FP less than Grain groups, and Hay groups had the least FP. In cages, both Chaff and Hay groups had significantly less FP than either the Grain or Control groups. FP did not reflect stimulus peck rates. Although Chaff groups pecked at their rack significantly less than either Grain or Hay groups, their FP was on a par with the birds in the Hay groups. Feather quality followed these trends. 4. The fact that these results were inconsistent with the original hypothesis led to a proposal for a modified hypothesis. Rather than the appetitive component of food searching motivation being redirected to feathers, it is the appetitive component of exploratory motivation, and the ability to reach the goal to update information about the environment is what feeds back to the motivation which leads to FP. This modified hypothesis is consistent with the results of this and many other studies and with modern concepts of motivation, foraging, exploration and food selection.

Feather traits in four southern populations of the Eurasian blackcapSylvia atricapilla: do altitudinal movements explain the differences?

Moult of birds is shaped by environmental and genetic drivers whose relative contribution to the structure of feathers may differ within and between populations. In this study, we compare some traits of tail feathers (growth bars, mass, rachis width and barb length) between four populations of the Eurasian blackcapSylvia atricapillabreeding at different elevations within the southwestern Palaearctic. We tested if these traits were related to the primary productivity of habitats (a surrogate of food availability) or were better explained as an adaptation to altitudinal movements. The distribution of primary productivity was positively related to blackcap abundance suggesting that the species tracked the most productive areas to breed. In this environmental setting, wing morphology (wing length, concavity and pointedness) suggested that lowland blackcaps were sedentary while blackcaps from highland areas were involved in altitudinal movements. The feathers of blackcaps inhabiting the highlands showed wider growth bars and rachis than those of the most productive lowland areas but did not differ in feather mass and barb length. Fast feather growth has been related to time constraints to moult and wider rachis to improve flight efficiency in migratory birds. Our results therefore suggest that differences in feather characteristics between southern populations of the Eurasian blackcap are better interpreted as an adaptive response to altitudinal migration than as a consequence of regional food availability.

Effect of stocking density on growth performance, feather quality, serum hormone, and intestinal development of geese from 1 to 14 days of age

This study was conducted to investigate the effect of stocking density on growth performance, feather quality, serum hormone, and intestinal development of geese from 1 to 14 d of age. A total of 450 one-day-old geese were randomly allotted to 45 battery cage (0.65 m × 0.62 m) pens according to 5 stocking densities (15, 20, 25, 30, and 35 birds/m2). The results showed that ADG and ADFI were reduced (P < 0.05) as stocking density increased from 15 to 35 birds/m2, but increasing stocking density did not influence (P > 0.05) feed conversion ratio (FCR) and body measurement traits. High stocking density significantly decreased (P < 0.05) the feather quality of back, thoracoabdominal, wing, and tail. No significant difference (P > 0.05) was found in serum concentration of adrenocorticotrophic hormone, cortisol, corticosterone, triiodothyronine, and thyroxine. The weight of cecum and intestine decreased (P < 0.05) as the stocking density increased. Increasing stocking density decreased (P < 0.05) jejunal villus height and villus height-to-crypt depth ratio, and increased (P < 0.05) jejunal crypt depth and ileal crypt depth in geese. Consequently, the high stocking density could depress the growth and impaired feather quality and intestinal development of geese. Under our experimental conditions, we recommend that the stocking density of geese from 1 to 14 d of age should not more than 20 birds/m2.

Effects of experimental increase in insulin-like growth factor 1 on feather growth rate, moult intensity and feather quality in a passerine bird.

Moulting is a crucial, yet often overlooked life-history stage in many animals, when they renew their integumental structures. This life-history stage is an energetically demanding somatic growth event that has particular importance in birds because feathers play a crucial role in flight, insulation and communication. Somatic growth processes are regulated by the evolutionarily conserved peptide hormone insulin-like growth factor 1 (IGF-1). However, the role of IGF-1 in feather growth remains unknown. In this study, we captured 41 juvenile free-living bearded reedlings (Panurus biarmicus) that had started their first complete moult and brought them into captivity. Then, we manipulated their circulating IGF-1 levels using poly-(lactic-co-glycolid acid) microparticles (microspheres) that provide a sustained release of IGF-1. The treatment increased IGF-1 levels but did not affect the feather growth rate. However, 2weeks after the treatment, birds in the increased IGF-1 group were moulting more feathers simultaneously than the controls and were at a more advanced stage of moult. Birds with experimentally increased IGF-1 levels had better quality feathers (measured by a lower number of fault bars) than the controls. These results suggest that an increase in IGF-1 does not speed up feather growth, but may alter moult intensity by initiating the renewal of several feathers simultaneously. This may shorten the overall moulting time but may imply costs in terms of IGF-1-induced oxidative stress.

Effects of rearing system (floor vs. cage) and sex on performance, meat quality and enteric microorganism of yellow feather broilers

This study investigated the effects of floor and cage rearing systems on performance, meat quality, and enteric microorganisms of male and female yellow feather broilers. Two hundred Xueshan chickens (42 days old; 100 of each sex) were divided into four groups, according to sex and rearing system (stainless-steel cage or litter floor). Male and cage-reared broilers exhibited better (P<0.001) performance and higher (P≤0.001) eviscerated percentage than female and floor-reared broilers. The interaction between rearing system and sex had an effect (P<0.05) on the percentage of breast and thigh muscles. Female floor-reared broilers presented the highest (P<0.02) percentage of breast and thigh muscles among all the groups. In both sexes, the abdominal fat content in cage-reared broilers was higher (P<0.01) than that in floor-reared broilers. Female cage-reared broilers exhibited better (P<0.05) meat quality of breast muscle than other groups. An analysis of welfare observations indicated that the feather quality of floor-reared broilers was better (P<0.01) than that of cage-reared broilers, whereas the gait scores were not significantly affected (P>0.05) by rearing system. The enteric microbiota assessment by 16S rRNA amplicon-based sequencing showed that Firmicutes, Proteobacteria, and Bacteroidetes were the most prevalent phyla in both rearing systems, and that the cecum was relatively stable in terms of microbiome composition. Floor-reared broilers exhibited a richer diversity of bacteria in the intestinal tract than cage-reared broilers, while alpha diversity was not significantly different (P>0.05) among the groups. The ratio of Bacteroidetes to Firmicutes and the abundance of Helicobacter and Romboutsia could potentially affect the production of broilers. These findings indicate that cage rearing improved the production of male Xueshan broilers, which may be due to the difference in enteric microbiota between cage and floor rearing systems.

Assessing the use of digital photographs for the determination of duck species, age and sex

Wing surveys are an important tool for understanding harvest and can provide information on productivity and survival which can complement traditional methods (such as ringing). However, storing and collecting wings at a national level is challenging and costly and limits hunter participation in such schemes. Digital photographs of wings offer an alternative method of capturing this data from hunting bags, but the accuracy and suitability of this method have not previously been adequately assessed. To investigate the accuracy of species, age and sex determinations from digital photographs of wings, we sent 97 photographs of wings which had been determined in hand to experienced duck ringers. Photographs were chosen of the three most commonly hunted duck species in the UK (mallard, teal and wigeon) and represented a range of lighting and feather quality. The accuracy of species (mallard 99.8%, teal, 99.4%, wigeon 98.6%) and sex (mallard 86.3%, teal, 80.6%, wigeon, 90.0%) determination was high. However, the proportion of wings with correctly assigned species, age and sex was low for mallard (50.3%) and teal (48.8%) and moderate for wigeon (79.7%). Our results support the use of digital photographs for the determination of species and sex for these species. However, further work is required to identify the factors which could increase the successful determination of characteristics, especially age, from photos alone. We suggest that further work exploring the use of photographs of the entire bird or specific features is likely to find higher determination accuracies, albeit at a potential cost to hunter recruitment.

Urban links to molt schedule, body condition and carotenoid‐based coloration in the house finch Haemorhous mexicanus

Animals in urban environments are exposed to novel conditions, such as habitat and dietary alterations, and night‐time light pollution, that can shift the timing and expression of life‐history traits. Birds are popular urban‐ecological study subjects, and in these feathered animals regular plumage molt is a critical process for maintenance of feather quality and their associated functions (e.g. thermoregulation, aerodynamics and communicative coloration). We hypothesized that environmental changes associated with urbanization might affect the timing and progression of molt. As molt is energetically and nutritionally costly, we also tested whether putative urban–rural molt differences might be explained by indirect effects of urban environments on aspects of health (i.e. body condition, sexually selected plumage color). We tracked body molt intensity during molt onset, peak and completion in both sexes of urban and rural house finches Haemorhous mexicanus, and related this to body condition and sexually selected carotenoid‐based plumage coloration. We found that urban birds began molting earlier, peaked at a lower molt intensity and ended molt later than rural conspecifics. We also find that both body condition and plumage hue in males explain variation in body molt intensity differently for urban and rural populations at various points during the molting period. Overall, we demonstrate that songbird molt patterns and the development of carotenoid‐based sexual ornaments can be altered in urban environments, and that rapid urbanization may have broader implications for molt dynamics, annual life‐history traits and sexual selection.

Effect of stocking density on performance, meat quality and cecal bacterial communities of yellow feather broilers

Totally, 315 42-day-old male Xueshan chickens were allocated into 3 caging densities, 14, 21 and 28 birds/m2. Each treatment was represented by 5 replicates. The body weight (BW), slaughter performance, meat quality, behavioral assessment, and the cecal microorganisms were detected at the market age. The results showed that the BW of broilers in the low- and medium-density groups was significantly higher (p < 0.05) than that of the high-density group from the age of 10 weeks. Only the feather quality of the broilers in the low-density group improved significantly (p < 0.05) compared with those of the other two groups. And, the abdominal fat percentage and the fat content of thigh muscle of broilers in the low- and medium-density groups were higher (p < 0.05) than those in the high-density group. No significant difference (p > 0.05) was noted in the other traits. The abundance of some microbial like Akkermansiaceae, Lactobacillaceae and Faecalibacterium may be correlated with the BW and fat content of broilers. The findings of this study suggest that increasing the stocking density decreased the final BW, fat content and the feather quality, whereas no evidence was found that stocking density caused changes in other parameters.

COMPARATIVE STUDY OF YELLOW-BILLED BABBLER (TURDOIDES AFFINIS) FEATHERS REVEALS UNIFORMITY IN THEIR MICROSTRUCTURES AMONG INDIVIDUALS

Though a few in numbers, investigations on feather microstructures from the early 20th century till date, have contributed immensely to various fields such as phylogeny, palaeontology, archaeology, wildlife forensic, biomechanics and so on. However, existing studies on feather micro-structures of birds endemic to the India/Indian sub-continent are few in number and limited in their scope. Also, no study has ever been conducted to compare feather microstructures of different individuals of a species from India. To address this issue, a comparative feather microstructure study of three individuals of Turdoides affinis, a passerine endemic to the Indian sub-continent was done. Select microstructure parameters for five different types of feathers were studied in detail. The molecular sexing method was used to elucidate the sex of T. affinis individuals for gender based differences if any. Results of the study identified that two of T. affinis individuals were female whereas one of them was male. Morphometrically, tail contour was the longest (9.63±0.76 cm) and bristle were the shortest (1.00±0.07 cm) feather. Semiplume had the longest barb length (1.73±0.04 cm) and shortest barbs (0.16±0.01 cm) were present in bristles. Subpennaceous barbs and knob-shaped villi, characteristic of members of the Passeriformes family, was also observed in all three individuals. This study records no significant difference in feather characteristics amongst the three T. affinis individuals irrespective of the differences in their sex and size. Systematically documented feather micro-characteristics of T. affinis in this study could be used as a species identification tool and would provide baseline data for the feather catalogue of Indian bird species being compiled at SACON.

Genetic parameter estimation for feather damage in laying hens

ABSTRACT Feather damage (FD) in laying hens is an economic and welfare issue globally. FD can be influenced by environmental, genetic, and nutrient factors. It is worth understanding the inheritance patterns and influencers of FD in layers for further improvement of feather quality. In the present study, tail and neck feather coverage of White Leghorn (WL) and Rhode Island Red (RIR) hens were recorded to evaluate FD. The genetic parameters of FD and their impact on the production performance were estimated. The heritability of the tail and neck FD for White Leghorn is 0.22 and 0.09, respectively, and the genetic correlation between them is 0.40. The heritability of neck FD of Rhode Island Red is 0.27. FD had a limited influence on egg production. Collectively, FD is influenced by many factors, including genetic factors, appropriate breeding strategies, and improved feeding environments, which are necessary to reduce FD in laying hens.