Hello, I was wondering isn't it ok to give bantams regular calcium and oyster shell like you do for big chickens like Buff Orpingtons or Rhode Island Reds? Because that's what I'm giving my bantams right now.
I haven't had any problems from it. Regardless of size, my mixed flock of LF and bantam eat the same pellets, crumbles, or meal. I even saw my 1.5 lb silkie gulp down a large japanese beetle today. As long as there's no visible problems, you should be fine.
Loving life with 93 chickens, 2 cats, a dog, and a snake. Tolerating the people.