Dogs Have Started Pooping Inside?

My dogs have decided to potty in the house, it seems they will hold themselves til they come in. Especially now that's colder, they will just stand at the door. They especially like to use one upstairs bedroom to poop in, even after they pooped outside! What's the deal? How can I change this around, I don't leave food down and have been crating them, but still I find dog mess. Help.

By kathleen blakley from Shelbyville, IN