Effects of multiple environmental and nutritional factors in laying hens

A large experiment on multiple factors and levels of those factors was carried out to test the hypothesis that in production experiments responses can be measured separately and then applied as if interactions are rare.Significant interactions of any order were indeed found to be rare, except for the interaction between temperature and dietary protein content.Responses to temperature, light intensity, protein content and feeding system were reasonably consistent with earlier reports.The rarity of interactions validates the use of a previously‐published additive model