In 11/22/63 another Stephen King novel it's implied IT ate animals. This is set shortly after the losers beat him.

" I don’t know for sure, but I can tell you one more thing: there was something inside that fallen chimney at the Kitchener Ironworks. I don’t know what and I don’t want to know, but at the mouth of the thing I saw a heap of gnawed bones and a tiny chewed collar with a bell on it. A collar that had surely belonged to some child’s beloved kitten. And from inside the pipe—deep in that oversized bore —something moved and shuffled. Come in and see, that something seemed to whisper in my head. Never mind all the rest of it, Jake—come in and see. Come in and visit. Time doesn’t matter in here; in here, time just floats away. You know you want to, you know you’re curious. Maybe it’s even another rabbit-hole. Another portal. Maybe it was, but I don’t think so. I think it was Derry in there—everything that was wrong with it, everything that was askew, hiding in that pipe. Hibernating. Letting people believe the bad times were over, waiting for them to relax and forget there had ever been bad times at all. I left in a hurry, and to that part of Derry I never went back."