Lots of times pups can eat something that's not good for them. I had one who used to eat sticks and have trouble pooping. I just googled it, and the advice was to bring them to a vet. There was some other advice on there you might want to check out. Good luck, and let us know how it comes out, so to speak.
http://www.petcaretips.net/constipated_dogs.html
__________________
Mike ~ Doting Dad to Jillie, Harper, Molly, Cooper, Eddie (RIP), Lucy (RIP), Rusty (RIP) and Jack (RIP).
Check us out on YouTube