I have been adding LA-200 (made by fox valley ) to their formula. It is a probiotic. I LOVE that product made by fox valley, it is the only probiotic I have found that works well with bunnies. The rest don't seem to do anything for them.
IR, I have no idea how you can mix it 2:1 and still have squirrels that are digesting. Just look up Zippy's thread and you will see all the issues I had with her on the fox valley. She was the worst with it, but all the other squirrels I had would be digesting OK at 3:1 then when I switched to 2:1, they stopped peeing and pooping and their bellies got REALLY big and they wouldn't eat. They didn't completely stop peeing, but it was enough to scare the living daylights out of me.