Is it normal for the second half of the poop to be softer and harder to pick up? I tried picking up the whole thing in one piece but the second half of her stool was harder to pick up.. Anyways our vet suggested that we switch her food to something with a completely different protein. So we...

OK so back short back story, my sister got a chihuahua, his name is Tank and is 3 years old. When he was younger he would poop up to 5 times a day. Was feeding him Blue Buffalo Puppy, her vet told her to put him on Purina ProPlan cause something to do with his digestive tract couldn't handle...