I lived on a corner property.  One morning I woke up to a dog howling.  I had never heard this dog before, but he lived next door and I had seen him.  I was up early in the morning and listened to the howling for about 15 minutes before going outside.  My neighbor's German Shepard had hung himself over a chainlink fence.  It was literally choking to death.  I went outside and ran over and extricated the dog from that situation, without even thinking it might try to bite me, it growled at first but then knew I was there to help him.  I untangled that German Shepard from certain death.   Don't know how it ended up in that situation, maybe it tried to jump the fence.  But it had a leash and collar on.
Les