Who so ever you like make it the first.

I like Poultrymen more so first he came, then Hen then came cock, as guys are always behind girls. then the chicken.

So simple. Use your mind a little

I believe that it is also same  case as there were 2 live on the earth who took the whole world in existence. So there must have been 2 (Hen and a cock) who do it all and they gone after thousand of eggs..

hehehehe :-)