Yorkie eating poops?

how to get my yorkie to stop eating poop? At the dog park or beach, she always finds a way to find a poop to eat or sniffs. I am always on my feet when i take her out, at home she is always digging and sniffing around for food too. her head is always down at the floor trying to find something to grub, constantly. I do feed her enough but i cant make her stop looking for food to eat and poop to munch on. She eats her own poops and my malteses poops. it is so gross!! and i am beganing to feel tired of it, like what am i suppose to do. I had bought medication for her to eat but she ended up vomiting after a couple tries. i stoped, i didnt thought it was good for her to vomit so much and all the time from taking the medications. How can i get her to stop? And is it because of what im feeding her. I feed her 1/8 cup of merrick wet and dry food every 4 hours.