How will I know if she/he's a roo?

[adeechickluv]

I have 4 lil chicks, and one of them is almost three times as big as them. I'm guessing he/she is also a week older (now about 3 weeks old). All four were sexed but I've heard there's a 10% chance they could still be a roo. Her/his comb is already growing and she's agressive and flighty. They aren't the characteristics for her breed (plymouth rock) but that's just a generalization, right? When can I tell if she's a roo?

 

[chickeepoo]

I had the same question- check the replies/pics in my post just below yours about sexing 6 chicks. The proof will be forthcoming regardless…

 

[BeardedLadyFarm]

Take a photo and post in the 'What breed/gender' section.

Hatcheries do make some mistakes. Barred Rocks are one of the easier breeds to sex.