My dog, Tyson (7 yr old 105 lb Black Lab Mix)has began this sudden anxiety and fear of going in the back yard. Tuesday I get a call that someone has found my dog. I rush home and check the fence (chain-link) and find no outs. There is one part of the fence that is lower (about 4.5 ft) so I figured that maybe he jumped over, but he had no scratches. We fix the fence by adding 1.5 ft in this one section and thought everything is fine. In the meantime, Tyson is very hesitant about going out to play in the backyard which is something he loved to do days prior. Last night I am coming home from work and I find him running down the side of the road. Again I check the fence and is belly and find nothing. I am convinced at this point that he is climbing the fence. What has sparked this new behavior?? I have had to force him to go out the past day, he will not go to the bathroom unless I am standing there with him. Any advice as to what could have caused this new anxiety??