My new born pups were also constipated then seemed to have diarrhea with out me even simulating them. I held off for a few days thinking it was normal and finally this weekend one pup became really weak. They also had red bums and some a little bloody. Ended up having to go to the vet and they had bacteria in their stool and needed abx. So I'd keep an eye on them, my one little girl went downhill fast. It's been a rough few days for me. She still is very weak and I'm having to supplement her.