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

A total of 2400 chickens from four commercial strains, Lohmann Selected Leg horn (LSL), Norbrid 41 (NB), Lohmann Brown (LB) and ISA Brown (ISA) were re ared and kept in aviary systems. Feather pecking behaviour was recorded by time sampling from video recordings at 38 weeks of age and condition of plu mage, 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 we eks. Feather pecking activity was highest in the medium heavy strains with ISA doing the most pecking followed by LB. Levels in the White Leghorn stra ins, NE 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 sign ificantly longer for feather pecking directed to the tail in contrast to ot her body parts. Bout size of feather pecking to the ventral part was signif icantly higher in LSL than in the other strains. Feather pecking activity v aried during the day and a significant effect of time (between 8 and 14 h a fter Lights on) was found. This was due to a rise in feather pecking activi ty over the day. This rise was significantly higher in the medium heavy str ains than in the White Leghorns. Condition of integument deteriorated quick ly during the laying period in all strains. NE had the best plumage conditi on in the last pan of the laying period, LB the worst. (C) 2000 Elsevier Sc ience B.V. All rights reserved.