I would think depending an the size rats they need, you would be feeding them every 1-2 weeks. I would start with a 1.1 pair(about 10-18 rat pinks a month) or a 1.2 trio. It really depends on how far you need to raise the rats up to for size. Warning you this, when you breed your own feeders(rats, mice, Bugs) You are MORE likely to get another animal than if you buy your feeders!!! lol Its true
Hope this helps a bit