The hyperstriatum and nesting behaviour in the domestic hen

Bilateral ablation of the ventral hyperstriatum resulted in hens ceasing to use trap-nests which they had formerly used. The appetitive component of their pre-laying behaviour was normal in form but was not directed towards the trap-nests, as it was in control birds. In the absence of trap-nests in a pen control birds laid in corners and were conservative in choice of site but both these characteristics were abolished by these ablations. Other bilateral ablations involving the Wulst had less drastic effects on pre-laying behaviour while bilateral ablations in the posterior telencephalon had no effect on this behaviour pattern.