It looks ok, but in all honesty, I would get MUCH bigger tubs. Moms with babies produce massive amounts of ammonia, and since the tubs are so small, there isn't alot of ventilation going on. You'll likely have to clean every other day, which wouldn't be feasible for anyone other than a crazy person

Also, rats that are too confined/too crowded will get bored/stressed and will chew. I have a couple of those tubs for storage and there are quite a few edges that ratties can get ahold of.

It's a good concept, but I really think they would benefit(not to mention produce better) from much bigger tubs that allow more ventilation and a place where they can get away from their feces/urine. If ammonia builds up, you're going to have rats with chronic respiratory problems. Sick rats don't produce(much less have time to eat because all they're thinking about is breathing), and if they do, the babies end up sickly.

Hope it helps some