Cottonseed is an excellent source of protein, but can only be used by ruminants. For non-ruminants, like raccons and pigs, the gossypol found in it is toxic. This means that you won't have to worry as much about other species eating your supplement. The cons are even in ruminants, too much gossypol becomes a problem with them, also. But as long as you are just using it as a supplement, this shouldn't be a problem.

I've seen it put in screen wire feeders. The lint on the seed keeps it stuck together enough that it doesn't fall out, but the deer can still pick it out.