I would add 25% of the commercial raw to his diet for say 1-2 weeks, transitioning is a personal thing, some can do it rt away, some not.
But in my opinion with raw I would do it slowly, say after 1 week cut back on the blue buffalo by say another 25%,add more raw, see how his tummy takes to the new food. Also monitor his stool for any change, if you see a change cut back on raw & wait until his stomach settles down.
You might want to add a probiotic or digestive enzyme during the transition -the honest kitchen makes a so called transition enabler called “Perfect Form” which worked for me. TheHonestKitchen.com
I will check back later to see if you have more questions, 1 of my angels needs her walk ,so i must go.
Good luck
