my girls don't have tear stains or bad breath either. they are both on Venison and Lamb diet. I use both NV and Primal brand. I switch and rotate between both. they are soooo spoiled and they get sick of eating one thing for a long time.
our freezer is always fulled with their bags and bags of food. my hubby thinks i am crazy. lol. he just laughs at me. i am thinking about trying a local brand call K9 cravings, my vet personally feed her dogs that brand. she's a huge believer of raw.