We pulled it out and it seemed to be food. We feed Greener Pastures whole grain chick starter. We had no problems with our first batch of chicks. I pulled out several chicks today that had this problem. A couple of them are very lethargic so I separated them and have been feeding sugar/vitamin water. We were very busy this weekend and I'm wondering if it built up over the weekend and they didn't eat. I'm thinking I may have added too much flax to the mix and maybe this is gumming things up. I had a little extra flax meal from cooking and thought it wouldn't hurt to dump the extra in the jar of chick feed since there is so little in it anyway. Oops!