Sure it is a he said she said case. You say it was stolen he says it was not.
It’s not he-said, she-said, because there’s evidence on one side and none on the other. He-said, she-said means a dispute in which there’s no basis for a third party to believe one side more than the other.
The main evidence is the location of the tractor. If that is all the evidence then it comes down to the word of the two parties about weather or not it was stolen.
My dogs and cats are permanently numbered (microchipped) and can be registered and tracable through both private and municipal systems. Not required, though - just a darn good idea. Some animals are tattooed.
I just came here to post that - animals being registered. Not as permanently as cars, but if your dog is lost, in Summit County, Ohio, with his required tag around his neck, he is definitely traceable to you. Other counties will vary.