This guide will tell you where to get the Hippogriff Feathers in Hogwarts Legacy
First, you need to unlock the nab sack for this and then make your way to Hippogriff Den, as shown in the map below.
It is recommended to go to settings and set the difficulty mode to story mode. Fly over to the location and catch one of them. They will try to run away, but you can still catch them by getting close.
After that, make your way to the room of requirement in Hogwarts and place the hippogriff in any vivarium to get the Hippogriff Feathers. Feed them and care for them once by using the food ability, just use the Beast feed, highlight the creature, and use the brush to make the item. Then you will get the hippogriff feather.