This is a great site to check for poultry processing regulations Poultry Processing Regulations and Exemptions
Besides your state you also need to check locally with the health department and the zoning department. Keep in mind, processing or value added production might be classified as industrial and therefore not allowed on farm or may require a special use or conditional use permit before you set up shop. Also check with your state to see how they handle farmer to friend or on farm only sales. Many states don't regulate this for under 1,000 birds, but you cannot advertise of deliver, the actual transaction must occur on the farm, Salatin gets away with outdoor processing because he sells his chickens to customer only on farm.
The other thing to remember, that in some zoning jurisdictions, if you take your birds to a licensed processor state or USDA inspected, and bring them back in plastic, you may not be able to sell them off the farm legally. This is product is not considered to be your farm product because you took the bird off-site to process. In other jurisdiction, you may be able to sell these birds off the farm, but will be considered a retail store and subject to regulations regarding retail stores (i.e. a license, public restrooms, refrigerated and frozen storage within the store. You may also have to provide a paved parking area with a minimum number of regular parking spaces and a handicapped parking area).