Effect of an early bitter taste experience on subsequent feather-pecking behaviour in laying hens

Recent studies showed that laying hens learn not to peck at bitter-tasting feathers from conspecifics. In the present experiment, feathers of newly hatched chicks were made distasteful by spraying them with a bitter-tasting substance (quinine). It was hypothesized that chicks could detect quinine and learn to avoid the downy feathers and the feathers of conspecifics later in life. Six groups of 10 high feather-pecking birds and six groups of 10 low feather-pecking birds were kept on litter. Half of each of these groups was quinine treated. Each bird in the quinine-treated groups was individually sprayed on a weekly basis for 25 weeks with a quinine solution. It was investigated whether the presence of quinine on the birds’ feather cover affected gentle and severe feather pecking. The result indicated that feathers made distasteful with quinine reduced severe feather pecking in young and adult birds as long as it was detected on birds feather cover.