Here's a quick way to sterilize them....put damp rag and the feathers in a microwave and "steam" them for one minute(feathers are delicate, so you may have to watch).

At the kennel where I worked, I was often given cat toys from the old lost and found, and was told to do this to sterilize them as much as possible.

Lily, Might-Hunter-Of-Feathers!

I am sure she will be ok...just keep an eye on her.

hugs!