Either someone has to give you some or have to get hunting training, find hunting implement, buy permits clothing and various etc and go out in woods or backyard, acquire the animal, clean it out and drag to place and hang then cut up, grind some meat and add sausage flavors or take the cleaned deer to a butcher who cuts deer. Sometimes if you hit a deer a responding officer may ask if you want it, think they give you permit. Then either you take it butcher or deal with it yourself and have sausage ingredients mixed with the ground meat
All that aside, not sure you can buy/sell wild game meat or maybe just deer in ny. But if you have or take meat to a butcher that handles deer they often will have option to prepare part or all of your meat as ground or sausage. There might be some place online where you can find farm raised deer that's been prepared as sausage. It helps to find someone who hunts a lot and gives away some to family or friends. Sometimes farms and orchards will have acquired deer nuisance permits and sometimes the people who clear out excess may give some away
& - checked online, there is one farm in Colorado who sells whitetail deer and is legal, but you'd have to check your state to see if it was legal to have it shipped there. Exotic animals from other countries I believe can be bought/sold since it's not native so you can buy things online or other stores if you can track it down. Technically, wild animals in a state are 'owned' and regulated by that state. Feral animals I think have no protection?
