H.N.
As an environmental educator, I have answered this question many times. You shouldn't worry too much about kids picking them up. Sure they have germs but not like the germs than you would find on a playground or on a grocery cart at the store.
You may have heard that feathers have bugs (lice) and shouldn't touch them. Well they do have "bugs" but they are bird "bugs", and if there are any "bugs" on the feather when you pick it up and they get on the child it wont take long for them to figure out they are not a bird and find somewhere else to be.
Do becareful not to collect feathers as this is illegal due to the migratory bird treaty act. Many nature centers etc, have to have permitts to have these in possesion even nests are protected from collection. I once heard about a man getting a ticket for having an owl feather in his truck when he got pulled over. He didn't know it was illegal.
Feathers are a great teaching tool, don't be afraid to pick it up, have kids try to identify the bird. Use it to make a feather inpression. Take a piece of paper and rub a crayon on the paper with the feather underneath. Then leave the feather for the next kids to enjoy.
If you ever have any other questions about nature let me know I would be happy to help you out.
You can also buy feathers at craft stores, they come in many colors and have been santitized. Kids love making crafts with them.
Happy feather hunting!