Why do you want to switch food? Is there a problem with it? The old saying, "if it ain't broke don't fix it" is a good one to follow with dog food.
LOL, that said I did start rotating foods when my boy was two. I kept him on the breeder's food, which worked perfectly well. But I rationalized that the same food all his life exposed him to a build up of whatever pesticides, growth stimulants etc that were used in the growing of the that food. So I rotate three main filler sources and three main proteins and none of one is in any of the others. I kept protein, fat and kcal/cup pretty close the breeder's food, which is my main food, because those work. I suggest you do this latter if the BB works for you. A lot of folks have loose stool problems on BB.
I like to see people research their food and I like this website for information on ingredients:
The information on dog food brands at that site is terribly out of date and I don't know why she doesn't take it down. Dont' look at that part.
I caution you on any sites that rate foods. Many are just one person's uninformed and biased opinion. For instance there is really nothing wrong with corn in food, apart from the possibility of aflatoxin and maybe too much corn. My main food has corn. Good luck. Food can be a really divisive topic and you aren't likely going to find much consensus.