Your first boy is a silver birchen, which means he carries two copies of silver. The other boy that is extremely gold, is a gold birchen with two copies of gold, the other boys that are not as gold are boys that more than likely have a split for gold and silver.
My main focus in the Marans are birchens and I don't keep the boys that have two copies of gold. I do however sometimes use the boys that carry a copy of each. It will take a bit of work to get where you want to be, but if they have superior body type and etc to the silver boy you have, it might be worth it. How old are these boys?
oh....and do you think that you can get a close up of the comb on that silver boy in the first pic? Particularly on the back part of the comb.