Methical - what is the butcher calling the minced meat? Pet food or pet mince something like that? Ask him whats in it. A lot of butchers put the end pieces into pet mince - those pieces that have slightly dried with them being in the display, whats not sold that day stuff like that. Just ask him whats in it. Some put 'lights' into it (lungs - although not sure if they're allowed to or not with bse as I'd stopped working by then) kidney, hearts, trim from the egdes of some cuts of meat like the flank etc;
Chicken wings are a great hit for the dogs, they chomp them up. My dog tries to swallow big lumps an can make herself sick with it, she chews the wings properly, but give her a big lump of meat and she'll do her best to swallow it in one go, if you're worried about her trying to swallow somehting thats too big then dice the meat up into smaller chunks, I usually dice anything to about 1" square (only takes a couple of minutes to do, if you don't like the feel of raw meat then wear a pair of latex or rubber gloves so you're not actually touching it, I know some people can't stand the feel of raw meat).