I am concerned about my granddaughter who is now 4 yrs. old. Potty training is an issue and since I have taken care of her for some days in a row recently, I have noticed that she has a poop every time she eats. This is when I wipe her butt. Upon exam, I note that her butt-hole, for lack of a more accurate term is not entirely closed, maybe open to the size of a pencil head. I compare her to her sister who is almost 3 yrs. old. I used to think the 4-yr. old had food allergies (which still may be). Her older brother has potty-training issues as well, and a few months ago at age 5.5 he was fully aware of the poop coming . Can you advise.