Is this the "Meaty Mix" canned food you're talking about?
Vets Choice: Holisitic Health Extension Canned Dog Food
Is this and the extra chicken her main diet?
If it is, the diarrhea may be because of lack of nutrition. This canned product is NOT a complete diet and is meant for supplemental feeding only (i.e. as a topping on dry food). It's completely lacking in bones/calcium and organs/vitamins/minerals and if she would continue eating this as a sole diet I'm afraid you'd end up with a sick little pup in no time. It may be a nice food, but she needs something else besides this and more meat.
If you want a high quality canned food she can eat as a regular diet, try
Nature's Variety . They have an Instinct line that is grain free or their "homestyle" cans look like chunky soup. The Merrick line of foods also seem to be pretty popular and go over well.