Abstract
1. The mathematical model of the hen's ovulatory cycle proposed by Etches and Schoch (British Poultry Science, 25: 65–76, 1984) predicts ovulation times for sequences of 2 to 9 ovulations only.
2. Continuous functions have been produced, representing the changes required to the parameters λ1, λ2, S 1, S 2, b 1, b 2 and b 3, such that the prediction of any sequence length is now possible.
3. This improved ovulation model is capable of predicting ovulation times and intra-sequence ovulation intervals for any ovulation rate between 0·5 and 1·0.
4. The improved ovulatory model lends itself to stochasticity. The rate of lay of a population of hens at a time may be modelled with the use of means and standard errors for each of the parameters in the model.
5. Age-related changes in the ovulation rate of the population may be predicted using a combination of three methods, which are consistent with published theories that account for the decline in performance with time.
Notes
1Mean intra-sequence interval.