I don't think your chicks were actually getting GRIT. What you were grinding up was essentially oyster shell, which provides calcium, what laying hens need for forming egg shells. All chickens need grit, or crushed granite, which goes into their gizzards and grinds up their food since they don't...
I am sorry for your losses but I can't speak to the causes. I also won't address the feed issues and will state at the outset that I am no authority in anything. Having said that however, I will express my opinion that no human can improve on the job a broody mother hen can do in raising chicks...
I'm so sorry this happened. You were trying to do your best for your babies and it didn't work out. I agree with the others in that it's best to feed the hen "baby food" rather than to give the babies an adult formula they can't handle yet. Oyster shell on the side won't hurt the babies, as they...