Blue Buffalo vs Canidae

[HutchOven]

Hi first post here. I'm looking for help on whether or not I should change my dog food. Right now my GSD is getting Blue buffalo adult chicken along with GNC hi and joint, and multivitamin supplements. I found a local Vet supply shop that sells Canidae and i've read it could be better.

I am mainly looking to switch to a poultry free food and I think the closest BB gets to that is there fish flavor which still has chicken fat in it. Is it worth the extra work to switch to the Canidae food? If so can someone recommend me to a flavor I should get?

Also, with all this grain free stuff there is out there now, is this only for dogs with allergies or is grain free just a better idea all around?