Wow, lots of variation in the statistics. I'll just add more info to the mix. I have two separate coops, for which I open separate bags of feed--less walking back and forth for me, and I can keep track of which coop goes through how much. Thirteen red sex links at the beginning of their laying career can make a 50lb. bag of layer feed last about 15 days. The mostly-black-sex-link coop (six of those plus an Ameraucana and a Brahma), all a year and a half, go through the same amount of food in 14 days. Fewer birds, about the same size, more feed. And they're thinking about taking a break from egg-laying! The feed is almost their exclusive diet, as I don't think the treats amount to much, and they've eaten most everything in their run.