I have some that don't do the f/t thang...so every Sunday I make my trek to Petco and spend an unnecessary wad of cash on over priced mice. Some of the employees will ask me, "what are you feeding these to?" and it's usually just a curious question...they've never refused to sell me anything. Petsmart, i've heard will refuse to sell you feeders. If you're worried they will refuse the sale, just keep your mouth shut, they don't need to know your biz