We lost a 6 week old today. They aren't growing as fast as we expected. They all have a bulging gullet full of Nutrena Meat Bird feed (size of a tennis ball), but not much meat on their bodies. The dead one was stuffed with feed but bony. They're in a dirt bottom coop with lots of grit, but it doesn't look like they're eating any. Tonight we replaced their feed with commercial grit. Am I on the right track of the issue? How do we save our flock of 50 meatsies??