First, there are really 3 options for getting your rabbit processed. You can do it at a USDA inspected facility, a state inspected facility or you can do it yourself. Each one has its own pros and cons.
Second, the regulations depend on HOW / WHERE you want to sell the meat. On your farm, at a farmer's market, in a store, online, in a restaurant...There are different levels of requirement depending on where you sell. Lets break it down a little.
1. Selling on your farm. This is the simplest and the least regulated. Small rabbit farmers (those who sell less than 5000 a year) fall under the "poultry exemption" which means you can process them yourself without state inspection. You have to include a tag indicating that the processing is not inspected but you can do it.
2. Selling at a farmer's market. Rabbit falls under the "game animal" regulations for farmers markets which require you to process in a state licensed facility. If you are selling by weight you also need to use a certified scale. If selling by the unit, no scale is needed.
3. Selling at a store, online or to a restaurant. Again, you must use a state licensed facility and a certified scale if selling by weight.
Note that NONE of the options required you to use a USDA inspected processor. According to the USDA rabbits are not "meat" but are "game" and are not subject to USDA inspection unless you are selling across state lines.
So those are the basics. Of course, if you are just raising meat for your own family, no regulations apply. Just use common sense and good clean cooking practices! :)