Genetics

[cricket92283]

Does the rooster or the hen determine how the chicks will look or the size and color of the eggs ?

 

[NatJ]

Does the rooster or the hen determine how the chicks will look or the size and color of the eggs ?

Both.
Each chick gets half of its genes from the father, and half from the mother.

Some traits seem to get mixed:
Dark brown eggs + light brown eggs = medium brown eggs
white eggs + brown eggs = cream eggs (usually)
big chicken + small chicken = medium sized chickens (usually)

Some traits are caused by dominant genes, and getting it from just one parent is enough for the chick to show it. Blue/green eggs work that way. So does rose comb.

Feather colors get more complicated--sometimes the chicks look like one parent, sometimes like the other parent, sometimes like both.

If you want to learn about chicken genetics, here are two pages that each have links to several other pages about genetics:
http://chickengenetics.edelras.nl/
http://sellers.kippenjungle.nl/page0.html