You could do a search on nutritional value of meat and find out about rabbits.
I do know from my rabbit breeding days that rabbits are no cholesteral, low fat and because of the short muscle fiber are more digestible than beef, chicken and pork. They are also higher in protien. Rabbit was used by the navy during WWII on the battleships due to the high protien content. A serving of rabbit is much smaller than that of other meats therefor using rabbit saved space and offered a high protien diet for the sailors. It is also considered the meat of choice for convalescents.
I used to sell off a lot of bunny kits to raptor rescues and snake breeders. I think that if they are the right size for your snakes they would be a great food source.
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Marcia - FroggieB Dragons
www.froggieb.com/MHDHome.html