Is comb development a tell tell sign?

[rkapfen]

I have a 5 week old BLRW that supposedly came sexed female but her comb development is very wide and is making me nervous. Is this a tell tell sign of a rooster or is there a chance she’s still a she?

 

[sourland]

Early comb and wattle development CAN indicate gender, but should never be relied upon entirely. Wait until secondary feathering signs appear to make any decisions.

 

[Gray Farms]

Agreed. That much comb at 5 weeks typically means cockerel. But like @sourland stated, it's not 100% accurate.