OH YAY!!! It's so exciting! So glad he is loving it, that's wonderful to hear. As for Ranger, it might just not be his flavor - maybe try the organic chicken (like you said), it tends to be a real favorite since it's so natural, it's very soft and different from the other meats - so maybe that'll be more up his alley. Maybe try it w/out the salmon oil too?
So excited for you!