58. The vast majority of broiler breeders are fed on a controlled diet from 15 days. This diet is considerably less than the birds would eat if fed ad libitum but the restriction is essential on welfare and economic grounds because birds fed to demand would become obese, fail to survive through the laying period and breeding would be severely impaired. We recognise that feed control is essential in these circumstances, as it is with the breeding stock of other species of farm animal. However, feed control raises a dilemma in that management practices essential to ensure good health and reproductive performance may impair other aspects of welfare.
59. Commercial broilers produced for the table are grown at a rate close to their genetic potential being fed at, or close to, ad libitum to reach a typical target slaughter weight of approximately 2.1kg at about 40 days of age. However, this is not the natural or most appropriate regimen for the welfare of breeding birds which need to reach a similar body weight over a growing period of about 18 weeks. Hence, breeding birds are reared on an entirely different regimen whereby feed intake is controlled to produce point-of-lay pullets with a body weight and condition which promotes fertility and which enables them to lay subsequently close to their potential egg production. They are fed on a regimen which aims for a steady increase in their bodyweight throughout rear of at least 7% per week.
60. Scientific experiments have demonstrated that severe feed restriction, during the rearing stage, in broiler parent stock can result in behavioural changes compared with ad libitum fed birds. These may include abnormal oral behaviours, such as stereotyped pecking at non-food objects and increased drinking activity. Studies of feeding motivation in birds fed on commercial rations have also concluded that because broilers have been selected to display a prodigious appetite, broiler breeders will be hungry for considerable periods of time. On the other hand, studies which have examined physical health have shown that feed control and slower growth have important welfare benefits such as improved immune system response and disease resistance, fewer skeletal problems, and significantly decreased mortality compared with birds fed to appetite.
61. It is clear that some degree of feed restriction is essential for welfare, but there is no agreed method of determining objectively at what level restriction becomes unacceptable. The birds we observed during our farm visits were fit, healthy and active. We saw little evidence of stereotypic behaviour but acknowledge that this may not always have been obvious during a visit. Excessive drinking is recognised as a problem which requires careful management. We conclude that whilst extreme feed restriction and ad libitum feeding are both unacceptable for the modern broiler breeder, a degree of control is necessary to optimise bird welfare.
62. During the first 6 weeks of life feed levels should be adequate to ensure good skeletal development. The level of feed intake throughout rear should be managed to achieve a steady growth, not less than 7% week-on-week, and the appropriate weight and condition at point-of-lay.
63. It is necessary to establish, as a matter of urgency, the point at which feed restriction creates a situation when the bird cannot cope with the hunger which results.
64. Research should be carried out to explore further the potential for alternative feeding strategies and management practices to alleviate hunger.