Feather pecking in domestic fowl is genetically related to locomotor activity levels: implications for a hyperactivity disorder model of feather pecking.

Feather pecking is a major welfare problem in egg production. Genetic lines differing in the level of feather pecking have been developed by genetic selection. In two experiments correlated responses in locomotor activity were investigated. Firstly, general locomotor activity was estimated using electronic transponders. A total of 325 pullets from three lines: an unselected control line (CON), a line selected for low levels of feather pecking (LFP) and a line selected for high levels of feather pecking (HFP) during 6 generations, were reared in mixed line groups and activity was recorded from 13 to 17 weeks of age using antennas placed in the litter. Locomotor activity was significantly higher in the HFP and significantly lower in the LFP compared to the CON line (lsmeans 0.72 vs. 0.62 vs. 0.57 records per hen per h for HFP, CON and LFP respectively). In a second experiment locomotion was recorded in 40 chickens from the LFP and the HFP line at 5 weeks of age during day time from 09.00 to 16.00 h using a very precise computer facilitated tracking system. Distance travelled was found to be significantly higher in the high feather pecking line compared to the low feather pecking line (lsmeans 122 vs. 99 m per hour in HFP and LFP respectively). These results are discussed in relation to the ontogeny of feather pecking and a hyperactivity disorder model of feather pecking is suggested.