How to tell a rooster?

One of my "hens" seems to be turning into a rooster, IMO. I will have to try to get a picture for some of the experts, but I was wondering if these are rooster behaviors? No crowing yet, BTW.

The bird is much more lanky than my other birds and seems to be taller.
When the bird finds a good bug, it clucks and one of the other birds will come over and eat it.
The bird always sleeps on the outside of the roost. The other three birds are closest to the wall and he/she is more out in the open.
This is the only bird that the tail feathers are still coming in. The other birds seem filled out, but this one has obvious growth on his/her rear area that look like black feathers. (the bird is a RIR)

Sound like a rooster?