If you do look for another rooster and want to
guarantee the offspring from your Marans carry the blue egg gene you'll want to use a rooster that is pure for the blue egg gene, such as an Ameraucana or Legbar. I personally wouldn't keep one that I knew hurt a chick. Though if he is young it may be he was over zealous or maybe just curious and could be something he'll grow out of.
I know how you feel about hatching so few pullets. I hatched 15 chicks last year and only got 3 pullets.
At least they are all pretty. Mine are also EE and I really want green eggs.
