So I fed my chickens back about six dozen eggs last weekend. I whirled them in the Vita Mix and what was left behind was about 4 cups of very pretty eggshell sand. I separated it out, baked it in the oven and then let it sit for a couple of days to make sure it was all dry. The shells by the way were not ground like flour, more like small "flecks". Yesterday I went out and put the shells out in the oyster shell holder and today....they were ALL gone. They ate all four cups??? Not only that but they had scratched around the ground getting every piece that dropped. They oyster shell lasts for a few weeks. Why would the chickens eat so much ground up egg shell in less than 24 hours? They are yard birds and they have a large 50x50 yard for 43 birds. Anyone anticipate I'll have problems??