I have a 1.6 year old rescue dog from the pound. Small yorkie mix but bigger than a regular yorkie. I will walk him for 30 minutes sometimes and he won't poop outside most of the time. He comes in and almost immediately he poops inside. I feel bad now. If he doesn't go I have started kenneling him. He poops a lot. Regular movements but 6 times a day and isn't eating more than a cup of food and his chews?Help, don't know what to do with him.

Did he get cleared by a vet? How long have you had him? Rescue dogs may come with all sorts of problems and need lots of patience. He may go inside because he was confined by an owner who never took him out. Sometimes the shelter has a little history. He will need exaggerated praise when he does go outside, lots of squeaky good dogs and patting and hugging and a treat sometimes, but not every time. If you can take him to a park with other dogs, he will learn a lot from them too, and will smell their urine and feces and see that it's good to go outside.
As for going a lot, if the vet cleared him, it's anxiety. He just needs tons and tons of calm loving attention, and his cage should be near you even at night.

A lot of it could have to do with the food you are feeding him. Commercial foods are filled with stuff like corn and other fillers, which cause the dog to have more bowel movements. When you introduce a higher quality chow, the dog gets more nutrients which means he needs less bowel movements.

The thing with rescues is no one knows their true past except them. If he was a puppy mill or from a BYB or a pet store, his only options may have been pooping in his cage or his “area”. After your walks, why don't you trying leaving him out for a few extra minutes. A lot of dogs have issues with having bowel movements while they are walking, but the exercise actually creates pressure on their bowels making them have to go, when he gets home and is resting, he feels he is able to let them go. When you get home, why don't you go in, get your glass of water and relax outside for a few minutes. This will give him an opportunity to relax and have his movements. Like Joy mentioned, give him lots of exaggerated praise. Good boys and a few pieces of kibble. Remember that with small dogs and puppies, any amount of food in their belly can cause pressure on their bowels.

Also make sure you are cleaning the area with a good enzyme cleaner. Vinegar and water does the trick, use more vinegar than water, and if you have it, add a few drops of tea tree oil. One of my rescues used to mess in her crate, after I started using the tea tree oil; there have been no accidents (knock on wood) for a while now.