I would not get the Blue Buffalo.
Acana doesn't look too bad. It has 34% Protein. I usually try to watch the protein and look for foods with a max 30% since high protein has been associated with kidney issues in our breed.
How big are the kibble pieces for Acana? My picky eaters seem to lean towards the smaller kibble and will at times purposely eat around the larger kibble pieces.
My favorite kibble for mine right now is the Solid Gold Wee Bits. It has 28% Protein and even my pickiest eaters seem to like it.
I mix foods but the Wee Bits is my largest percentage in the mix.
Solid Gold Northwest - Products - Just a Wee Bit Bison Small Breed Dog and Puppy Food