what about a draft, a change they don't like can get them to do silly stuff, the one thing you are going to have to watch is growth rate with these, the shavings can and will get caught in the crop and hold up growth rate.
did you change something , feeders, waters, where they are
I keep mine on PPtowel for the first 7 days, feed on the floor for 2 days, then switch to the feeder, so they get the idea to the difference