I kept finding very crap quality feeders around, I went this route to control food supply and to gut load before CD and freeze.
I believe the large ones are the 110qt Sterlites from walmart (they're around $25 each) and the small ones are 30ish quart and are $10 each.
And no, that's not a ping pong ball. That's my Himalayan girl Migoi curled into a ball. She's a 2nd generation hold back for future breeding.
Chewing is a learned behavior, not a natural one. If you start with rats that don't chew, you won't have this issue long term. You can cull it out too, but it can be expensive. It's much better to start with pet stock than pet store stock for this reason. I had one that did chew out of a hole that a previous chewer had started (she escaped and was recaptured) but she hasn't chewed anything since, so I haven't culled her. I want her genes too.
I also didn't start with just a small hole around the spout, I drilled and cut a panel of hardware cloth in and I used machine screws and washers to hold it in place, so there isn't a lot of room to chew. The smaller ones can worry the plastic a bit, but as they grow up, they rapidly become too big.