Generally, 16-18% is a good protein level for our breeding colonies. I use Harlan 2018 for nursing mothers, and Mazuri 6F for the breeders. We always have weaners around 60-80 grams at 3 weeks of age. The mothers have large litters, my average is right around 14 pups per mother, personal highest is 17 just this past month to a first time mother. (That was a surprise to walk in on!)

I'd rather not go too high with protein (above 20), because males don't need such a high protein level, and many rats do show the skin allergies with the high protein content. ( I have at least 4 out of 40)

I always recommend Mazuri 6F or 9F to people, and if they use any other feed to try and mimic the ingredients closely and protein, fat and fiber as well. I'll have to look at chick feed, but the crumbles and lack of hard gnawing doesnt sound like a good alternative just on the waste level. You'd have to put in it a bowl and I figure the rats would quickly soil or throw around the food.

Becky has offered non medicated hog feed as an alternative, or a high qualtiy senior dog food. I trust Becky as she is the queen of ratty knowledge around here LOL .

I believe she also uses the hog feed along with her mix, and she has something around 40 lovely pet rats. (She raises mice for feeders)