My parents had a Collie that wasnt fixed for the first 5-6 years of his life. One summer he kept escaping the electric fence and we couldnt figure out why he all of the sudden would keep doing it. We checked and knew the collar was still working and even saw him get shocked while escapaing one time. So the last time he escaped my mom had mentioned how he was found hanging around the neighbors dogs. I was like wait are those dogs fixed? Thats probably whats motivating him so much lol. We got him fixed and never had that problem again.