Online he cheapest is rodent pro. If your near Indiana or Ohio or Pa they do shows, you may combine a show to save on shipping.
This past summer I was in Texas with a good friend. He had a good friend that just so happened owns the mouse factory. I needed info on mouse breeding. I'm hard to impress on a high level, but Ray the owner gave me a 20 minute lecture on mice. I know my mouth dropped. The guy knows mice to a molecular level. Feed, housing, types of grain, why dog food is bad long term, levels of fat and protein at each stage of life. I can also say he prepares mice better than the meat we buy for ourselves.
[urlhttp://www.themousefactory.com/[/url]
I've also heard great things about the Big Cheese Rodent Factory.
Many people use them for high quality stuff
We breed some of our own at the shop. When we need, we order locally. I also don't need much, and in the cleveland area, so I hit a show for a few bags of pinks from rodent pro then try to repack with vacuum packing.

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Thanks for reading.
Big Tom
www.HerpZillA.com
www.HerpHelp.com