
Hi Sarah, I use Arden Grange for my 3 dogs (an Alaskan Mal, Cavalier KCS & Samoyed). I couldn't recommend it more - the dogs absolutely love it, they were on Royal Canin before which they didn't really care much for, but now they get so excited when its feeding time.
Ive only ever tried the lamb & rice adult variety as Ive been pleased with the results and haven't needed to change. The food pieces are small in size and ideal for my Cavalier, so I should think it would suit your Mini Schnauzers just fine.
My girls always have small, firm poos and this is important for me too as Cavaliers are prone to anal gland problems but my girl has had no problems since being on AG.
Another thing about AG is the customer service is excellent if you ever have any queries. (And no I dont work for AG, I'm just a very satisfied customer!!)