Answer:
I am the home for feathery animals.
I help engines spin and pants stay up.
2 in a corner 1 in a room 0 in a house but 1 in a shelter.
Only one color, but not one size, stuck at the bottom, yet easily flies. Present in sun, but not in rain, doing no harm, and feeling no pain. What am I?
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
I am your mother's brother's only brother in law. Who am I?