A good place to start to get information is your county extension office. Each state has its own rules so you need to talk to someone local about all of this. Each county, township, city , or even HMO can have their own rules but with all those animals I'd guess you are in the county so you don't have to worry about town or HMO.
The rules will be different if you are selling meat or eggs or baby chicks. If you are keeping them for yourself there probably aren't many if any rules in the county but check anyway. How much meat or how many eggs you will be selling might kick you into a different category. If you are crossing state lines the other state may have different rules. It could be different if you are selling to a restaurant versus individuals, or in a farmer's market.
@aart in Arkansas it was fairly easy to become a certified NPIP inspector, I have not checked here. You had to go to a class to learn how to to the testing. I think that class was offered twice a year. Other states have different requirements and cover different tests. Maybe what tests are requires influences how hard it it to become a certified NPIP inspector in that state.
@C Dohrer NPIP (National Poultry Improvement Plan) was set up as a voluntary program (States could join if they wanted to and 48 have) to mainly stop Pullorum, a disease that was pretty prevalent and was causing a lot of damage to the poultry industry. It is a government program that worked, now Pullorum is pretty rare. Many states have added other diseases to the testing requirements but not all states have the same. NPIP generally only comes into play if you are selling across state lines or maybe hatching eggs or maybe showing birds. The rules of the state where you are selling are the ones that apply. It's certainly worth asking your extension office about NPIP and whether you need it. I believe in knowing what the rules are so you know what you are working with.
I believe you said earlier you are planning on selling meat. This is where I'd expect them to have rules regarding handling and cleanliness and possible regular inspections if you are doing the butchering. Selling meat is probably your biggest hurdle and some of that could be how much you are selling and where.
It's all doable, you just have to figure out how to make it work for you. Good luck!