The photo is really not close enough to see any great detail but I'm leaning towards a cockerel unfortunately as the comb looks larger and too pinkish for a 4-5 week old chick and the legs are quite thick, but as I say, from that distance it's very much a guess.
Yes mixed breeds can look a bit odd. I have some that are barred from their father and have large floppy combs and beards and moustaches from their mother, Not exactly an attractive mixture and certainly a bit quirky but I love them and at the moment they are laying really well compared to my pure breeds, even if I do have to hunt all over the place to find their eggs..... I found 43 last week in an old jackdaw's nest in the eves that required a ladder and crawl boards to access!
Hope I'm wrong and yours turns out to be a pullet that lays as well as mine.
Sorry about the poor pictures, I caught him/her this evening & took these two pictures. It's exaxtly 6 weeks old now. Cheers!
Glad to hear your mixed breeds are such good layers, i hope mine don't start playing hide & seek with their eggs! :-D
It is hard to tell, but I am thinking that your boy gave you another boy, lol. If that is as much comb as it seems to be, at that age, then I'd say cockerel.