Oh yeah one more thing, I keep the grit under the coop with the water. The oyster shell I will put in the coop near the food if I need to add it to their diet. Just my thinking.
I use the smallest galvanized pails I can find, 1.3 quarts. I got mine at TSC.
I drill 2 3/32 holes oblong shaped in the bottom, I let the drill ride for about a 1/4, to drain moisture. I do that for the granite grit and the crushed oyster shell. I also use 1 for water under the coop,so no holes...