I have a BB gun and a back yard full of the Varmints
But seriously...
Rabbit production is one backyard industry that promises a bright future. Why' Because almost 99 per cent of the rabbit is useful - the meat for food, the fur for clothing, paws and tails for trinkets, and the manure for soil improvement and for new energy source... bio or methane gas.
The returns from rabbit raising vary from place to place and from time to time. So rabbit producers may either expand or close down their projects on the basis of local and national demands.
However, rabbits are perhaps the most economical and profitable of all kinds of livestock. They can utilize inferior feeds and still provide quality meat and fur. Moreover, with a better quality feeding program, they can increase bunny production thus allowing a higher profit margin for the producer.
A good rabbit raiser strives to raise as many bunnies as possible from one doe within a year or during her productive life. Good management includes the wise selection of initial breeding stock and the determination of how much time and capital is to be invested in the project. It also includes good care of the does, bucks, bunnies and paying alert attention to housing, cages, sanitation, and record keeping.
http://www.appropedia.org/Back_Yard_and_Commercial_Rabbit_Production_15
Squirrel is even leaner, I think, but tastes about the same. But tree rat is kind of tough.