title: Comparison of social ranks based on worm-running and aggressive behaviour in young domestic fowl.
abstract: Worm-running is behaviour in which a chick runs carrying a worm-like object while flock mates follow and attempt to grab the object from its beak. We hypothesised that social ranks based on worm-running frequency are stable over time and are positively correlated with social ranks based on success in aggressive interactions when older. At 8-12 days of age, we scored worm-running in 17 groups of 12 female White Leghorn chicks during three 10-min tests. Based on instantaneous scans at 5-s intervals, the bird carrying the 'worm' most often was placed in rank one and so on down the rank order. These tests were repeated at 68-70 days of age. An aggression index for each bird was calculated as the number of aggressive acts given, divided by the number given and received, during three 1-h observation periods when the birds were 68-70 days. Ranks obtained in worm-running tests were positively correlated over the two age periods (P < 0.05) but were not correlated with ranks based on the aggression index (P > 0.05). Our results indicate that worm-running ranks are not predictive of success in aggressive interactions. Instead, worm-running fits some criteria for play.
authors.affiliation: Department of Veterinary and Comparative Anatomy, Center for the Study of Animal Well-being, Washington State University, P.O. Box 646520, Pullman, WA 99164-6520, USA. scloutie@vetmed.wsu.edu
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cloutier
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Newberry
authors.forename: Kristen
authors.initials: K
authors.lastname: Honda
mesh_terms: D000374:Aggression; D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight; D003163:Competitive Behavior; D005260:Female; D006608:Hierarchy, Social; D011200:Poultry; D012919:Social Behavior; D012930:Social Dominance; D014743:Videotape Recording