Hi Dave,
Never in my 13 yrs of HB ownership have I had this problem w/a customer and I deal with pet owners constantly. I use citrus boost all the time. I, myself have a dog with allergy problems and for the past 11 yrs. my dog has had outbreaks as you describe on his belly. It is most likely from the dog rolling in the grass or other plant matter. Typically diagnosed as “environmental allergies” You should ask the customer what the vet’s conclusion was. I treat my dog with benadryl or something stronger if necessary and it gives the relief needed. Our products are fairly mild but I always ask my customers to keep off for an hour after I’m gone. If the dog was allowed to lay on wet carpet then possibly it may have irritated his sensitive skin. It sounds like the owl problem is a bit more serious. Where I live we have many predetors including owls, fox and several bear. Hopefully, the dog owner and dog are smart enough to know when to stay inside. Good Luck!
Anna