I feed Purina Adult Chicken and Rice and was considering occasionally throwing in a bag of Performance. Seeing that Performance is in the Proplan line, can I do this without risk of upsetting the dogs' digestive systems?

If you have to ask that question, I would assume that your dogs are getting the same food day in and day out. Dogs that are getting a varied diet can switch from one food to the other with out any problem. My dogs get a variety of different foods and brands and never have a problem. What they are not getting from one they get from the other, and they and their intestines are much healthier for it. Mix in as many differnt brands as you are able. A healthy intestine has no problem switching from one food to another. Mix it up!

I feed ProPlan performance (which is chicken based), and I routinely buy a bag of a non-chicken based regular ProPlan once a month or so. It comes in beef, lamb, and there's a salmon variety too. I tell my puppy buyers that as long as you stay in the same family of products, you don't have to worry about the famous gradual switch.

I like to rotate protein sources. I don't eat chicken every night. I really don't think dogs should eat chicken all the time either. And I think we don't give our Labs' digestive systems enough credit. I don't gradually switch anything and have never had a problem. And I don't have any problems (well, most of the time, but then again, I'm aging) having chicken one night, fish the next, then beef, then pork, then vegetarian, etc...

You answerered my question....thanks!

Do you ever include a bag of SELECTS?

Nope - I just do the regular and performance ProPlan. I don't do gimmick foods like large breed or senior, and the only reason I occasionally use the sensitive stomach is that it's a salmon based and it's another protein. Nothing to do with the stomach.