OMG! I know the feeling when they are not in your sight and outside the fence, it happened when my husband and I were sharing the lawn chores and I thought Murph was in the house where I had left him and hubby let him out and I had left the gate open so then when we called for him, nothing...luckily hubby realized it pretty quick and Murphy was two doors down
It's the same feeling as when you lose sight of your human children!!
So how did he get back home?