Further Experiments in Feeding Thyroid to Fowls

In an attempt to learn more of the properties and functions of the thyroid gland, several investigators have tried feeding fresh or desiccated thyroids to fowls. During 1924 and 1925 experiments of this nature were made by the writers. In view of the varying reports of other investigators, our results are considered of sufficient interest to warrant their presentation. They include effects of thyroid feeding on moulting, egg production, weight, plumage color and plumage structure. MOULTING Forty White Leghorn hens were divided into two equal lots and fed identical rations. To make the environment natural and equal for both lots, ten birds to receive thyroid and ten controls were put in each of two identical colony houses, both of which had out-door yards. For a period of six weeks, beginning November 1st, the twenty thyroid-fed hens were given desiccated thyroid (Armour and Co., 0.2% iodine) at the rate of 196 . . .