Diurnal rhythm of feather pecking behaviour and condition of integument in four strains of loose housed laying hens

Abstract

A total of 2400 chickens from four commercial strains, Lohmann Selected Leghorn (LSL), Norbrid 41 (NB), Lohmann Brown (LB) and ISA Brown (ISA) were reared and kept in aviary systems. Feather pecking behaviour was recorded by time sampling from video recordings at 38 weeks of age and condition of plumage, keel bone, bumble foot, body weight and length and curve of the beak were recorded at various intervals during the laying cycle from 17 to 69 weeks. Feather pecking activity was highest in the medium heavy strains with ISA doing the most pecking followed by LB. Levels in the White Leghorn strains, NB and LSL, were considerably lower. The overall bout size (number of pecks per bout) did not differ significantly between strains, but the bout size was longer for feather pecking directed to the dorsal part of the body by White Leghorn strains. Across strains the bout size was on average significantly longer for feather pecking directed to the tail in contrast to other body parts. Bout size of feather pecking to the ventral part was significantly higher in LSL than in the other strains. Feather pecking activity varied during the day and a significant effect of time (between 8 and 14 h after lights on) was found. This was due to a rise in feather pecking activity over the day. This rise was significantly higher in the medium heavy strains than in the White Leghorns. Condition of integument deteriorated quickly during the laying period in all strains. NB had the best plumage condition in the last part of the laying period, LB the worst.