what brand are you feeding your dog? Have you been feeding him/her with that particular dog food for years? I used to feed my dogs with commercial dog food but after switching to homemade recipe, they love it.
Even if the dog food has not been recalled, it could still be a bad bag. IF in doubt, stop feeding it and return it to the store...most will give you a full refund if you tell them you think it is a bad bag. If you encounter trouble, call the company, most dog foods print their 800# on the bag or you could google them to get it. Since you have 5 dogs and they all have diarrhea, it is something they all have in common, but maybe not the food...you'll need to be a detective....what else do they all share...is there a treat they all share (like chicken jerky or dog bones or ??? ) or could they have gotten into something in the yard or on a walk? IF the diarrhea keeps up for more than a day, call your vet for something to stop it....dogs can become dehydrated pretty easily from diarrhea and then you can be in serious trouble!