Anytime you're switching diets, I'd suspend use of oils, personally. Since diet switches can sometimes cause loose stools - you don't really want to put add'l oils in the mix, bc they would exacerbate looseness, if there was any. If it were me, I might try the lamb again - without the oil - and if that didn't work, I would then try the organic chicken, as most dogs go bonkers for it.
As far as that smell, they could be detoxing a bit - so I wouldn't worry too much about it at this point. Again though, I'd stop the use of oils until digestion is settled.
As for the color, not all of the medallions are like this - but the lamb is and I think maybe the venison is a bit too. I'm not sure why, but it must be something in the oxidation process and/or the nature of the meat itself.
GOOD LUCK! It's exciting to switch to new diets!
