Originally Posted by
arentspowell
I've never heard of diarrhea as an allergy symptom. Allergies typically manifest themselves as with itchiness, flakiness, redness in the ears/paws, or rashes/break outs in the belly area. Loose poops, especially later in the day, is very common in puppies. Over feeding can also be a cause of diarrhea. Not saying you are overfeeding necessarily but if you're feeding his normal amount and then adding lots of treats on top of that, it could definitely be causing diarrhea especially if the treats are bigger and higher in calories.
When our dogs were puppies, I used their kibble as a treat and just subtracted it from their daily portions. I saved the better stuff when I needed something high value and even then I would adjust the dinner portion accordingly if it was an intense training day that required lots of treats.
Also, I can't remember how old your puppy is but I remember grain free wasn't appropriate for puppies because of the calcium/phosphorus levels. Not sure if this has changed but that was the general consensus a few years ago when mine were puppies.