Have a question about my dog

He is a lab going on 11 yrs, one of the better dogs I've had.

My neighbor (200 yds away) talked to me today and said the last 2 weeks my dog has been going over and crapping in his yard. Never happened before.

We get along and he likes dogs, and he did not say anything last week because he thought is was a fluke. But now its continuing.

What would cause a behavior change, and more to the point how do I retrain?

I am going to tie him at night now and when we leave, but this is a working farm and I am NOT going to have a farm dog tied up during the day every time I go out to the field to spray, make hay etc.

He is supposed to earn his keep killing groundhogs and rabbits that try to raid the garden, which he does well.

I am thinking about a radio fence, I had one 10 years ago that we trained him as a pup, but lightning storms would trigger the collar. What are the better models/brands?

Or other ideas?
thanks


�Any man who thinks he can be happy and prosperous by letting the government take care of him had better take a closer look at the American Indian.� - Henry Ford