Just thought of something - you can also try using Orijen instead of Acana - it's the same company but the Orijen is grain-free and tends to be a bit more appealing smell-wise.
I also just remembered that I'm the one who suggested you get Tikka a small bag of the SD to help the switch to Acana LOL - well, that backfired didn't it? LOL
I can't remember if you were on the thread talking about Honest Kitchen. You could try mixing that in with the Acana (and some SD just for Tikka's switch) too. It'll kind of "soup" it all together and the people who use it say their "picky eaters" love it.
They are little buggers aren't they? LOL I have to literally rotate something different for each meal with Alice to keep her eating - I just started using Nature's Variety and I rotate daily through their raw, kibble, and canned and all the different flavors and then some regular raw chicken or beef from the grocery store, that works really great and the nature's variety is excelent food. (I throw Orijen kibble in the mix for her too so I don't waste the bag I bought and she eats it perfectly fine as long as it's not everyday

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