Are they a boy or a girl?

This is by far the most popular question. Really at this age there isn't a true way to tell with the untrained eye. There are a few wives tales like:

If the wing is split its female,one solid wing is a male.

When picking them up, males will pull legs up and females will let them hang.

I've also been told that overall there are more females. 

At about 3-5 months if it crows then you have a rooster!

Females lay eggs at 5-6 months at the average rate of 1 egg a day.

Also asked a lot is what's the difference between eggs with chicks and eggs at the store?  Eggs with chicks are fertilized by a rooster. Eggs at the store are not. You don't need a rooster for a hen to lay an egg.