My dog hasen't poopeed in 3 days. What should I do?

What kind of dog, how old is your dog ? What are you feeding your dog ?

He is 5 months old, a Blunose pitbull, and I feed him Taste of the wild canine dog food.

Without an x ray kind of hard to tell. It could be a bowel blockage. Young dogs are liable to swallow anything that could create this. I don't know what his environment is. Is he outside most of the day, or in the house on his own?

I would suggest taking him to the vet and have him physically examined.

Good idea.

Have you changed his foods recently? Sometimes it's simply a matter of the animal not eating for several days. If so, it may be a matter of not having anything to "go" with, but it is still a good idea to find out why he may not be eating.

If your dog is not having bowel movements for more than a day or two I would be very concerned about a blockage and have him to the vet as soon as possible - especially if he is not eating or drinking. Regardless, if he is eating and you are absolutely certain he isn't going that is dangerous, too. A dietary change can throw them off for a day or possibly two, but 3 days is far too long. At the very least call your vet and see what (s)he recommends.

Hugs, Didi