Investigation in the Queyras!

The story takes place in 1698, when a feather was stolen from the schoolteacher's hat. These feathers were very valuable, as their number symbolized the ability to teach reading, arithmetic and Latin.
For a laugh, one of his pupils wanted to play a trick on his teacher. He took the ornament and left clues as to how to find it.
to find it. Maybe you can help him
find it!