They get lots. from the layer feed, sometimes milk, we take the shells from the eggs we used and crush them and put it in their food. fair bit of Cal and Mag in the Water (on a well), and all the rest are rock solid. New one on me. I'll keep an eye on them, not sure which its from.
I've seen that happen to my next door neighbor turn out to be a Calcium deficiency he had to give his Birds more calcium
They get lots. from the layer feed, sometimes milk, we take the shells from the eggs we used and crush them and put it in their food. fair bit of Cal and Mag in the Water (on a well), and all the rest are rock solid.
New one on me. I'll keep an eye on them, not sure which its from.
I have some crushed oyster shells I'll put out to make sure they got enouch calcium available.. got 7 duck hens and 13 chicken hens.