I provide grinding grit especially when chicks are in the house or caged, they can’t go get rocks on their own. I give to adults too based on my yard, what is in it… in theory there is plenty of little pebbles, rock stuff but some parts of the yard not so much, and if weather has my birds in a less “grit” containing area confined then absolutely I give it to them. Oyster shell is my extra calcium source so I just put some out for them too.