[The vitamin A supply of laying hens including during rearing. 1. Testing of mixed feed with a varied vitamin A supplementation in chicks and young hens].

In seven experiments with 46,310 young animals from hatching to the 21st week the vitamin A supplement varied between 0 and 10,000 IU per kg mixed feed. Feed intake was significantly diminished in three out of seven experiments when chicken feed was given without vitamin A supplement. In the young chicken period 1,500 IU vitamin A supplement were sufficient for optimal body weight development, in the young hen period native carotene was sufficient. The variation of the body weight of the individual animals on the 126th day did not show any connection with vitamin A supply. The carotene content of the rations was sufficient to prevent deficiency symptoms. The livers and yolk sacs of one-day-old chickens on average contained 114 and 56 IU vitamin A/g substance when the parents had received mixed feed with 15,000 IU vitamin A/kg. There is a positive relation between the vitamin A supply of the young chickens and hens and the vitamin A content of the liver.