Here are a couple on calcium and growing chicks. I used to have others but the links don't work anymore.
I don't have the one on the roosters. If I remember right it was @bobbi-j that had the link. But then it may have been @ChickenCanoe My memory is not always as good as I think it used...
There are studies that show that too much calcium CAN lead to medical problems in growing chicks and roosters. I don't know of any studies made on non-laying hens but you would guess they would be similar. CAN does not mean they take one bite and fall over dead. CAN does not mean each and...