Research Note: A validation of an image-based method to estimate chicken comb size.

Chicken combs carry important information about the individual, especially the size has been related to sexual reproduction, health, and social signaling. Comb size is usually estimated by weighing removed combs or by calculating the product of the comb's longest and highest dimensions (LHA) to approximate comb area based on measures of a ruler or caliper. These methods have several shortcomings including invasiveness or imprecision.

Coup in the coop: Rank changes in chicken dominance hierarchies over maturation.

Chicken dominance hierarchies or pecking orders are established before maturation and maintained by consistent submissive responses of subordinate individuals, leading to stable ranks within unchanged groups. We observed interactions of 418 laying hens (Gallus gallus domesticus) distributed across three small (20) and three large (∼120) groups. The observations were performed before sexual maturation (young period) and additionally after onset of maturation (mature period) to confirm stability of ranks.