I get Zukes Mini naturals from Petco. They are small but I still cut them into fourths so they don't get too much while we train. It's okay though they don't know the treat was originally bigger.
I ordered some Yorkie Yummies from Chattiesmom last Sunday so were waiting on those to arrive. From everything I have read they might not be so happy to get the Mini's anymore after they get a taste of the YY's.