Chickens are different than other species as they are judged without the presence of a showman. They are placed in cages and the judges come around and compare them to each other and the written standard for each breed and variety listed in the American Standard of Perfection. You don't register chickens, you just enter them into a show(usually two or three weeks ahead of show). You don't have to raise them, but I don't recommend a feed store for your source. Find a breeder here online. Bath them a week befor the show, and do some final touch ups the night before. Put it into it's designated cage and hang out at the show. The judges go through and judge them, and that afternoon or the next morning(depending if it's a two day or one day show) you can check out. Search online for an entry form or contact the show secretary to get an entry form.