Calcium intake in relation to ovulation and oviposition when access to oyster shell is time‐restricted or unrestricted

Abstract

1. White Leghorn hens were fed either a conventional diet containing 40 gCa/kg from oyster shell, or one low in Ca (3 g/kg) with oyster shell offered separately. 2. In experiment 1 access to oyster shell was unrestricted; in experiment

2. Access was time‐restricted to the first 6 h of the photophase of the 14L:10D photoperiod.

3. Irrespective of time‐restriction, hens offered oyster shell laid heavier eggs, but shell thickness was reduced.

4. On days on which only ovulation occurred, time‐restricted hens consumed significantly less Ca than unrestricted hens.

5. In contrast, on days on which only oviposition occurred, time‐restricted hens consumed significantly more Ca than unrestricted hens.

6. These results suggest that when access to oyster shell is time‐restricted to morning hours Ca consumption occurs in response to a Ca deficit persisting from the previous period of shell calcification.