Hi Michael
A fair few dogs have allergies to cereals (wheat, barley) so sometimes it is best to go for something that doesn't have any cereal based dog food. I think mine are on chicken and rice diet (18% protein maintenance) that they have been for 3 years with no problems. If your dog has no signs of any allergic reactions to the dog food, I would stick to something that you are getting good results from. However when my youngest was 16 weeks it was on a higher protein diet of 22-23% until it was about 5 months and I dropped it to 18% protein. I use Trophy dog food but I only have 2 dogs and it's £40 a bag lasts 1 month but it's quality stuff. If I had 10 dogs I would probably use something a bit cheaper.