Are you sure? They are awefully small to make a judgement about what's good and what's bad. My chicks went thru so many changes in color. Of course I know nothing about Sussex and the way they develop! But they sure are cute! 
I just got rid of a rooster too to give the other one a better chance. So fair enough it is the right thing to do. But he was a lot older. What happens if you get rid of those other roosters and the one dies? Do you have a replacement option?
I would find a way to allow him to feed and get what he needs. Maybe split the groups and put him with others chicks (hens).

I just got rid of a rooster too to give the other one a better chance. So fair enough it is the right thing to do. But he was a lot older. What happens if you get rid of those other roosters and the one dies? Do you have a replacement option?
I would find a way to allow him to feed and get what he needs. Maybe split the groups and put him with others chicks (hens).