how do i think of these things?

i just went to a local hardware store to get a key made. inside they had these little baby chickens ( very cute ). that got me to thinking, how do hens make eggs? do they have to have sex with the rooster? i thought hens laid eggs all the time so if that is the case then either 1) you have to have a lot of roosters or 2) a very "active" rooster. if hens do not have to do this then what is the need of the rooster? why are they around?

on a very side note, grey's was great last night. i felt so bad for george. the thing is, i really like gray too. i also like baily. those are my top 3 on the show. and they all have very different attitudes. i can see a little of myself in each of them. i still think i am the most like george.