The use of animal bones in witchcraft is common. They are being used as the way so that a witch can be able to communicate in the world of the animal spirits. You can use this bones as the place to ground or hold a spirit of an animal in this world. But doing this will not hold their spirit permanently. It will just serve as their home in this world when you call them. You can place them in containers or put them in your altar. If you want to carry them if you will use them then you can put them in a crane bag.
One use of the animal bones is that they could be used if you like to call a mythical creature. But you will need to have the bones from different animals that if you combine them, they can be of the mythical creature. For a dragon, you will need bones from a snake, bone of an eagle or its feathers and bone from a lizard. The use of the bones of animals could be combined into the use of ritual jewelry. If you ask for a direct contact or for an easier communication with the spirit of an animal that owns the bones.
As sometimes it is not easy to have bones of animals, so if you only have delicate part of the bones, you can place them in vials. You then attach into a chain so you can carry it as a necklace. If you wear bones of animals, you can have some of their characteristics or powers also. One example is to be able to see in the dark, have bones from an owl. Animal bones could be tied in wands and other things in witchcraft.