Doesn't like to go potty anymore

by Cheri
(Tucson)

I have a Jack Russell, Trouble, who has recently decided that he won't pee or poop in my boyfriends back yard. This is a new development as he had done it previously. Now he will only go if we take him for a walk, which isn't the answer. We have tried synthetic urine to entice him, but it doesn't work. When I take him home to our house he has no problem going. It is just at his house. He is currently going on 27 hours without urinating because he won't go in the yard and we are trying to break him of the walk habit. We have 2 other dogs who don't get to go for walks throughout the day. We had to put him into a kennel in a room by himself today so that he doesn't pee on everything while we are at work. I can't stand this. I know that holding urine leads to utis and urinary stones but don't know what else to do!

Suggestions pls!!!