My 8yo dog has always been taken out to go pee and poop. We recently installed a doggy door so she can take herself out to a new enclosed dog run. She independently takes herself out to pee but not to poop. We have tried prompting her to go outside 3-4 time a day (thru the new door) but we keep finding poop inside the house. How do we get her to associate the need to poop with taking herself outside? I'm stumped!