REARING CONDITIONS AND NEEDS FOR SPACE AND LITTER IN LAYING HENS

Five groups of four hen reared in battery cages, and five groups of four hens reared in floor pens, were tested in an operant conditioning apparatus which allowed the hens to enlarge their cage by key pecking. Cage size could be varied between 1600 and 6100 cm2. The variable size section of the cage floor was covered with wood shavings (Condition 1) or wire mesh (Condition 2), whereas the permanently available surface was covered with wire mesh. Each group of hens was tested over 4 days in each of the two conditions. Birds reared in cages work less to enlarge their cage than birds reared in floor pens. Thus hens habituate to space restriction and this habituation appears to take place in a relatively short period (less than 6 weeks). None of the rearing treatment led to an increase in the work done to get access to litter. This confirms that hens are not prepared to work to get access to litter and that there is a lack of need for this substrate. The results of this experiment appear to confound two major criticisms of battery cages (lack of litter and space restriction).