There is no certainty in anything other than the sex-linked hybrids and autosexing breeds until they either crow or lay.
At 5 weeks, barnyard mixes are variable. If you can see the same hatch, the boys do have larger combs...but at 5 weeks, there could definitely be a slow developer.
Marans, if a good line, *should* telecast early...I could tell mine at 2 weeks...however I also had a precocious girl that was an "if" for sometime.
RIR and Plymouth Rock also tend to telecast by 6 weeks with the boys with redder and larger combs...but I've had precocious girls in that as well, and slow developing boys. 8 weeks is better...you often have a pretty good clue...but I've had 12 weekers still holding out. Usually the hold outs are slow developing boys...but sometimes precocious girls will fool you too. (I gave a hen away once thinking it was a roo.)
Brahma develop slowly. The pea comb can drive you nuts as to sex for many of them. I would be most hesitant with the Brahma.
So you can get indications within hatch-mates, but no guarantee especially at 5 weeks. Better feel at 8 week. No guarantees.
The only one I'd feel pretty safe is with the Marans. Those boys do develop early.
If you want more birds, pick up some Red Sex Links. They lay like crazy, are congenial, and from a reputable breeder or farm store, you will KNOW you've got females. That beauty of the sexlinks.
LofMc
