The effects of exogenous oestrogen and progesterone on laying and nesting behaviour in the hen.

1. It has been shown that if oestrogen and progesterone are given to ovariectomised hens nesting behaviour will occur. Thus if these hormones are given to normal hens the excessive pacing found in some hens before laying might be reduced. 2. Experiments showed that oestrogen produced no noticeable effects and progesterone caused a high incidence of delayed oviposition and abnormal behaviour.