I'm not sure that what I do is training in this department. My dogs do know "aus" which is not always executed correctly (ie they know it but don't always do it). Either dog will let me take anything. I generally do not mess with BTY2's food but I could. Ironically, BTE2 likes her food messed with. She likes company for dinner, too. Either can be hand fed with respect for the feeder. (ie they are gentle about it) BTY2 should have been named "Mikey" in that "Mikey eats anything". She's easy to pill with just a bit of peanut butter or cheese or or or. BTE2 on the other hand cannot be fooled. It is necessary to "say Ahhhh" and insert pill in back of throat. If fed in a dab of peanut butter, disguised in a bit of steak, hidden in cheese, the pill will be detected, the disguise eaten and the pill spit out.
On the other hand -- I have had picky eaters and chow hounds in pairs before. I learned the hard way to think about it and not offer the picky eater's food to the chow hound when both were right there and I was in the way. So I don't do that.