"MANY more problems"? What do you see as other problems? Or are you just overstating the temperament issue as "problems" (Pleural)? I am not trying to downplay the temperament issue, I totally agree I don't want aggression in a breeding bird. But I would also like to learn what to look for in a good Delaware, that is why I wonder if you are seeing something other than the comb. Tail set, color, etc? The question I asked about the possibility of housing in a small solitary pen with no other birds, whether that might affect temperament, has gone unanswered.
The comb is the least of his problems. His tail is a big problem and it looks as if he is very short, shallow and may even have some skeletal issue unless it is just the angle of the picture.
Generally you can keep a lot of cockerels together if there are no females in the pen. Put them together early if possible.
Walt