There is really no reason for this Easter egg to be where it is in the game. Honestly, it's most likely one of the developer's love letter to Wolverine. The adamantium hand is hidden between some stones in the forest to the north of Neuhof (see the map below for exact location).
Unfortunately, you can't use Wolverine's hand in the game; you can't even pick it up. But that would probably ruin the realistic approach of Kingdom Come: Deliverance. To be honest, seeing a character run around with claws instead of fingers would be pretty hilarious to say the least.