It would be my guess that the feet are removed from rabbits who are killed for the fur trade.

I can't imagine that it would be profitable to raise rabbits to adulthood for ONLY their feet. What would someone get for selling a rabbit's foot to be made into a keychain? A dime maybe? The whole keychain, after dying the fur, preserving the foot, attaching the hardware, etc., sells for only a couple dollars. So I can't imagine them paying more than a few cents for an unprocessed foot. So, there has got to be more sold then JUST the feet - no one can raise a rabbit to adulthood for five cents of cost.

I don't wear fur, and I don't carry rabbit's foot keychains. It would creep me out. But, I suppose, if you are already killing the animal for meat or fur, you might as well use all the parts you can, and not waste anything. Using the rabbit's feet for keychains is no different from using the cow's skin for leather shoes, I guess.