I have a 4 year old border collie cross, which has been house trained for the past three years. In the last six months he has started peeing and pooping in the house. He can be outside all day long and as soon as he comes into the house he immediately runs downstairs and poops. We can take him for a walk and again poops once he is back inside. There has been no significant changes in lifestyle, the only thing I can think of is that he was "fixed" about a year ago. We have resorted to keeping him tied up in a certain part of the house during the night, and keeping him outside when we are not here. I am a stay at home mom, so I am here all day long to let him out when need be. I am not sure what to do, and am afraid we are going to have to either give him away or have him put to sleep. Any suggestions would be greatly appreciated.

This is not at all expected behavior. Some times as a dog matures, it develops problems like that, but 4 years is a little late. Neutering is no cure all, but should have helped, not led to a problem.

Tying him for the night likely was a good move. I tend to suggest a crate, but at his age, he may adapt to the tie down better. You may want to use it more of the day when you are occupied and can't keep an eye on him. You might even move it around so he can be near you. Otherwise, use doors and gates to keep him in the same room as you. Watch him carefully. When you see him sniffing around or circling, be ready to correct him. When he humps up his back, start with a ''Bad dog!'' in a quiet, but firm voice, and take him outside. Likely that will not be enough, but give it a chance. Dog are individuals, and each needs different discipline.

Catching him in the act of marking calls for stronger corrections than the
Otherwise effective "Bad dog!". When it misbehaves, throw it on its back, and
Growl "Bad dog!" right in its face. Hold it down until it lifts one back leg
To show submission. You can pick him up with your hands behind his front
Shoulders and hold him up with his back to you. Keeping him far enough away
To keep his head from smashing into your face, hold him until he stops
Struggling and relaxes. With his size, you will want to leave his back feet on the floor to hold his weight. Others like the squirt bottle. Fill it with water
And a little vinegar or lemon juice. Give it a squirt in the face as soon as
It misbehaves. Dogs hate that.