We have a 12 week old puppy who for weeks 9 and 10 when we first got him we would take him outside into his pen (which is a fenced area right off our deck that is approx 20' x 20') and he would pee and poop there. Granted we could take him out there for 30+ min at a time and he would only pee and then come into the house to poop, but eventually he got the whole pooping outside thing. Now, he has learned that there is a huge fenced in yard just over the snow piles we built to keep him from going out into the yard while we were potty training him. He now refuses to go poop in his pen and will only poop out in the yard. If left to run in the yard, he poops right away, even if I have spent 30+ min with him in his pen. He gets a lot of praise and treats for pooping in his pen, but has decided that that is not where he wants to go and that my yard is a better place. I know I should just be happy that he goes outside and paws to go out, but I have 2 small kids and do not want poop all over my yard where my kids will run into it or fall into it. I am also not willing to follow him around with a pooper scooper each time. There is a reason for the dog pen! Does anyone else have any other ideas?? We have gone out with him on a retractable leash into the pen so he can roam the pen but yet we keep him from the yard. We have also tried just a tie rope so he can only get around the pen but not into the yard and we are not around so he can do what he needs to without being watched. I am at my wits end with this! Please help!! :)

Have you tried walking him around the backyard on a leash and then when he goes to poop quickly race him (you might have to pick him up) and put him in the pen.

I have seen a lot of dog trained to use just one part of the yard this way.

So you have fenced "off" his pen rather than fencing it "in?" By that I'm asking if his pen is enclosed on all four sides.

Area training is much more time consuming than simple housebreaking. It sounds like you've done a good job with the latter, now he has to figure out that the "pen" area is where good things happen if he goes and the other areas get him no benefit at all.

If he's small enough and you're quick enough, putting him in the pen area whenever he starts to go will teach him where. Lavish attention and maybe a treat when he goes in the pen will teach him it's a good idea. If he can't get out of the pen, being ignored until he goes in the right place will teach him both things, especially if he gets to play in the big yard only after he "goes" in the pen.