Results obtained were as follows: 1) Summer experiments: Three hens injected with a total of 300, 400 and 600 IU Prolactin during 2 to 4 days, showed broodiness. A cock injected with a total of 400 IU Prolactin during 4 days showed clucking. 2) Autumn experiments: Of ten hens injected with a total of 200 IU Prolactin during 4 days, two showed broodiness.
