My dog had really foul breath ... and really foul stuff out the other end ... on both Orijen and the grain free versions of Acana that we tried (we tried the Pacifica, the Ranchlands, and the Prairie - fish, red meat, and chicken in other words).
The vet suggested that the problem was twofold - too high a protein level for the dog as a family pet (back end) and no "good carbs" like oats for the tummy to cut out the offensive breath. He is a fan of Orijen but indicates that in his opinion it is good for working dogs but too rich for family dogs.
She did well on the regular Acana (with grains...and lower protein than the grain free) except that she did not chew it - same with Orijen and other Acanas.
We rotate a few similar foods for her - TLC (coming out of rotation..she is no longer interested in it...mixing it with Canidae so she'll finish the bag!), Canidae ALS, and Royal Canin Medium 25 are the three in rotation right now ... seeking a replacement for the TLC in the future...maybe Go!Natural....that worked well in the past
She does best on Royal Canin IMO. Fewer poops, softer coat, no bad breath, no farts, plus not eating everything in sight (ie: leaves, garbage, my kids underwear) when she's on that blend. The more holistic, the more grain free, and the higher protein....increases poops, stinky breath, and stinky farts and has her seeking out other non-desirable food on walks, etc. At least that's how it works in my dog.
Plus, I live close to the border and can get the Royal Canin - made in Canada - for $42 / 30lb bag at Petsmart in Buffalo
vs $59 at Petsmart in Fort Erie
. Canidae is $46 in the USA and $57 here....not as big a spread...but still disgraceful.