1. Provision of light and dark periods can influence broiler behaviour and impact bird welfare. Determining how offering light in different patterns, such as intermittent (INT) lighting, impacts birds is necessary to determine ideal management practices. The objective of this research was to establish the impact of 9 h of darkness (D) provided in one (1 × 9D), two (2 × 4.5D) and three (3 × 3D) periods on Ross 308 male broiler behaviour.2. Each treatment was replicated three times and behaviour was recorded over 24 h at 32-34 d in one pen per room using infrared cameras. Behaviour was assessed via instantaneous scan sampling at 10 min intervals.3. Birds in the INT treatments spent a lower percentage of time preening. Broilers spent most of their time resting during scotoperiods. The INT lighting schedule birds spent a higher percentage of time feeding and drinking and less time in comfort and exploratory behaviours. Broilers appeared to anticipate all scotoperiods and increased their feeding activity at the beginning of each photoperiod, regardless of period duration.4. Providing 9 h of darkness over 24 h in one, two or three scotoperiods had minor impacts on behaviour. Birds prioritised resting during scotoperiods, while during the shorter photoperiods between scotoperiods birds on INT lighting schedules prioritised nutritive behaviours. Broilers appeared to anticipate the beginning of each scotoperiod and adjusted their feeding behaviour to compensate for time off feed during scotoperiods.
1. This study evaluated whether lunar periodicity was associated with variation in productive traits and mortality in commercial broiler breeder hens. Production records from Cobb 500 heavy breeder hens (n = 17,548), collected between 2016 and 2021 on a commercial farm, were analysed.2. The synodic lunar cycle was divided into eight consecutive phases of approximately 3.7 days each. Two production seasons were defined according to rainfall patterns: December-April (wet season) and May-November (dry season). In addition, three laying periods were considered: early production (weeks 26-28), peak production (weeks 29-34) and late production (weeks 35-56).3. The lunar cycle significantly influenced the number of eggs laid, laying rate, percentage of hatching eggs and the number of cracked eggs (p < 0.01). The number of double-yolk eggs was not affected. Egg production decreased towards the middle of the lunar cycle and increased towards the final phases, with higher production around the new moon compared to the full moon.4. Significant interactions were observed between lunar phase and both production season and laying period. Mortality showed variation across the lunar cycle, with the highest values occurring around phase 6.5. These findings suggested that lunar periodicity may be associated with short-term variation in productive traits and mortality in commercial broiler breeder flocks, highlighting the potential relevance of lunar-associated environmental rhythms in avian biology.
1. In this study, genome-wide population structure, genetic differentiation and homozygosity patterns were investigated between Silkie (SLK) and White Leghorn (WLH) chickens, using high-density autosomal SNP genotypes. These breeds were selected as they have markedly different breed histories and productive performances.2. Principal component analysis revealed complete genetic separation between the two breeds, explaining 75.82% of total genomic variance and indicating strong divergence. Genome-wide differentiation showed heterogeneous patterns across autosomes. The top 1% of windows (FST ≥ 0.7467) were used as an empirical threshold for prioritising regions showing elevated differentiation.3. The study identified 20 protein-coding positional candidate genes, including TRHDE, GABBR2, SEMA3A, SEMA5A, IGF1, SOCS2, AR and NLGN4, which have roles in neuroendocrine, behavioural, growth and reproduction.4. Breed-specific runs of homozygosity (ROH) revealed marked differences in autozygosity, with Silkie chickens showing substantially higher genomic inbreeding coefficients (F) of ROH (mean FROH = 0.396) than White Leghorns (mean FROH = 0.175). Island analysis identified 30 islands in Silkie and 19 in White Leghorn chickens, predominantly located on macrochromosomes. There were breed-specific and partially overlapping differentiated genomic intervals, highlighting concurrent differentiation and homozygosity in the two breeds.5. The results showed substantial genome-wide differentiation between Silkie and White Leghorn chickens. This provided a population-genomic framework for prioritising candidate regions for maternal behaviour, reproductive physiology and egg production.
