Chimera went on my group hike today and found a dead, dehydrated mole at the end of the trip.
The other dogs wanted to see what he had, and he would growl and/or bark when they came close and then run away, so they started chasing him around in circles. I let them do it, because then he didn't have the opportunity to settle down and eat it. When it was time to get into the car, he wouldn't get close to me while I had the other dogs leashed to me. I put them into the car while he settled down safely away from the road. Then I held the leash out to him and said "time to go", our cue for leashing up and leaving the park. (He usually comes right over when I say it, because if he doesn't, I just stride purposefully toward the exit and he gets the picture.) At first he ran away from me with the dead mole in his mouth, but I repeated the cue, approached slowly and calmly, and held out the leash. On the fifth try he let me reach over him and clip the leash to his harness. This was a moment where he decided to trust me that I would only leash him up and not try to take away his prize, and it was critical to not break my promise and ruin that trust.
I told him "let's go" and backed up away from him, and with just a small amount of tension on the leash, he relented and moved with me, but his body language was stiff and suspicious. I stopped and made a big fuss over him, and he started wagging his tail and came toward me, and I rubbed his sides and his butt without reaching for the dead mole in his mouth. I backed up again, and we repeated this two more times, to build his trust in me and teach him that it's safe to come to me when he has something valuable.
Finally I led him to the car and opened the door to his crate. He walked up to it, then stopped, conflicted. At this moment I swiftly pulled the mole from his mouth, put a little pressure forward on his harness, and said "in the car!" He automatically jumped in, and got a big jackpot of treats!!