I, also, use the cheaper brands of dog food available for my rats... they have a higher grain content and the right protein content to produce good growth and healthy pups. I usually use Ol Roy or America's Pride (50$ for $8) mix that with sunflower seeds, some cracked corn and rolled oats and thats the mix I use for all my rodents (gerbils and Rats) All of them produce well on it.. It takes me about 2.5 months to get all my females to breeding size and my males are breedable at a little over 6-7 weeks.
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Lucien
1.0 Columbian Redtail Boa (BCI)(Sutekh)
2.2 Leopard geckos (2 Blizzards (Caine and Goliath), 1 het Blizzard (Lilith) and 1 Tangerine Albino (Tequila Sunrise ...Tiki for short))
0.1 Savannah Monitor (Kiros)
13 rats
5 Gerbils
2 Dogs (Loki and Storm)
2 cats (Sahara and Hercules)