Plasma concentrations of thyroid hormones in growing pullets and laying hens reared under two tropical climates and fed on diets with different energy concentrations.

1. Blood samples were taken from growing (14-week-old) and laying (36-week-old) hens reared in either a temperate or a hot, humid climate and fed on 2 dietary energy concentrations (10.03 or 11.

Effect of diet and natural variations in climates on the performance of laying hens.

1. Laying hens raised in 3 natural tropical environments were fed on 2 series of diets with a view to defining the optimum combination of climate and dietary energy. 2.