As LongEaredLions suggested, we always encourage our members to adopt, rather than buy from stores or breeders, but we understand that our furbabies come from all over.
We don’t exactly allow discussions of breeding per se, but your question isn’t about that exactly, so I would suggest you could get a very good idea of breed standards by looking them up on the American Rabbit Breeders Association website. They probably have set sizes, and possibly photos.
Once you get a mixed breed, it’s a guess. My Mini Rex, Spockie, who was mixed, ended up being 8lbs at his max. weight. Usually you can expect 5-6 lbs. in a mixed Mini Rex.They make lovely pets.
If you do get your bun from the breeder, ask about its diet, because some breeders feed for different purposes and you may need to change it. Check out our bunny info. section for good tips on setting up your habitat and stocking up on the best basics for bunny. 