Yes.
To preen just means to groom the feathers. Birds may do this to their young and possibly other birds. If they like you, they might try to do this to your hair.
This could be a trick question. No other animal lays eggs in human hair while that hair is still attached to a human head, but hair that falls off or is cut off and blows away in the wind may be collected by birds and incorporated into their nests, where they will lay their eggs.
if they choke on a bunch of them.
No. Birds have feathers, not hair.
They should be, but be cautious. Some companies do advertise human hair, but it's human hair blend or human hair mixed with animal hair.
no they have feathers
Mammals are not covered with feathers. Mammals grow hair, but do not have to be covered with hair. Birds are covered with feathers.
No, they have feathers.
NO. Even if the cat had "human-like" hair it wouldn't be human hair because it grew from a cat.
The width of a human hair is 0.0018 cm.
teacup Yorkies do have human hair