Chicks should not be fed egg shells or ground oyster shell. They are not grit which is ground granite. They are to increase calcium availability to egg layers and can harm chicks.
Vet wrap aka self adhesive bandage wrap works pretty well for my rooster. You can find it at Walmart near the bandaid although I use it enough I ordered a batch.
I change his bumblefoot dressing every other day and it stays on well. He has a layer of 4 x 4 of honey gauze folded in a triangle...