Our feedline broke down Friday morning. Well, the feedline was running, but running empty because an auger wasn't pumping grain into the barn. My wife went out at 7 AM to let the birds out and they were pretty irate that they hadn't been fed yet. They are usually fed immediately after the lights go on at 4:30 in the morning. It took me a couple of hours to get the auger working. You should try working in a barn with a few thousand hungry birds, I thought they were going to eat me for breakfast.
Anyways, the next day our production was down 3 or 4 percent, which is a lot. Even though it's a few thousand birds, they usually lay the same amount of eggs each day, give or take a few, with production decreasing slowly thoughout the year. A drop in production like that is usually indicative of a feed or water problem.
I guess if they were accustomed to being fed on a different schedule they would adjust, but with reduced feeding hours birds would be competing for feed and, as somebody said, the smaller birds may not get enough.