DESIGN OF NEST BOXES FOR LAYING CAGES

1. ISA Brown hens were housed in groups of 4 in cages with different designs of nest boxes provided, to determine the effects of nest box design and management on their use and on the prelaying behaviour shown by the birds. 2. There were 5 treatments: control (C); a wire-floored nest box attached to the back of the cage (W); a nest box containing a fibreglass rollaway hollow (N); two rollaway nest boxes (T); a rollaway nest box, protected by a partition from the main part of the cage (P). 3. The holes in the rollaway nests in treatment N, T and P were shut initially, but the proportion of eggs laid in these nests only reached 50%. This proportion rose to over 80% when wood shavings were added daily, but fell to below 30% when rollaway holes were opened. These rollaway hollows are apparently not suitable for use in laying cages. 4. Use of nest boxes in treatment W varied between 60 and 80%. However, when pre-laying behaviour was recorded (in 19 hens) two birds which laid in the nest boxes nevertheless showed abnormal behaviour. 5. Individual hens had on average 29 to 60% of their pre-laying behaviour overlapped by that of others in the cage. Nesting space for at least two birds is probably necessary in a cage for 4 birds. However, in treatment T pre-laying behaviour was disturbed by hens moving between the two boxes. This would be avoided by provision of one box big enough for two hens. 6. Soiling of hollows resulted in dirty eggs and suggested that nest boxes for laying cages may have to be provided with doors to prevent hens from roosting in them.