Housebroken Dog Pooping Inside and On Sidewalks?

I have a six year old Lhasa/Bichon who has been housebroken since puppyhood. For about the past year or two, she has been pooping where we walk; the front and back decks, the walkway to and from our cars, directly where we step to get in our cars, and recently practically on the threshold of the front door. We have five acres of pooping area, but she insists on going precisely where we will be stepping.

She also goes behind our couch almost every day, every time we leave the house and even while we are in the room. We leave our doors open so they (her BFF, our 4 year old Yorkie) come and go as they please and she shows no fear of anything out there, but will do this even after she has just come back inside.

She knows this is a no-no because she hides or stares at us with her head down. We have tried every form of correction, negative and positive, and she simply doesn't care. It just gets worse and worse. Now she won't even walk on the grass, she just goes where she likes, even if we are watching, walking right behind her and telling her no. And it's not the feel of grass she's avoiding because she has to walk on rough gravel to get to our cars and I'd think that would feel a lot worse than grass. It can't be for attention because she's held a lot, usually jumping up to sit on our laps most of the time.

As for changes, last year our teenage son passed away during the night and she was present when we found him and right beside him as we fought to resuscitate him, watching him, and us, and looking as sad as I've ever seen a dog look. And as the house filled with rescue personnel, we had to kennel the dogs and I know that not knowing what was going on was scary for her as well. There were a lot of new people coming and going for a while, also, but the pets got a lot of attention from people just wanting the comfort of holding a pet for a while. And though this behavior was going on before losing our son, it has progressively gotten much, much worse.

We feed her Nature's Balance Grain Free Sensitive, in an auto-feeder (so she doesn't guard the food from the Yorkie). They also have an auto-waterer. She doesn't seem to over-eat, either. And she's got a clean bill of health from the vet, too. Please help, we are at our wits end.

By LJC123