Help! is this polish bantam male or female????

[Cliopadra]

Helo, I was wondering, does anybody here know how to spot the difference between a male and a female polish bantam chicken???
Because a few months ago we got three polish bantam chicks and we were told they're all hens, but I'm starting to suspect the biggest chicken, Dwalin, might just be a cockerel?because he(?) looks a bit different? And is pretty aggressive?

I don't know, what do you think???

 

[JedJackson]

Cockerel. It's growing the long, pointy male feathers in the crest, and that is a sure sign.

 

[HuffleClaw]

Cockerel. See the start of his rooster tail feathers (probably better wording for that).

 

[Crazy for Chickens!]

I'd like a picture of the saddle feathers, please. Also, what's the age?

 

[Birds of a Feather]

Probably a cockerel.