If you could post some closer photos of the bird it would help out a lot. The main thing that says rooster is the tail. Hens simply do not have the sickle feathers (long-curvy ones) that your bird has. Their tail feathers are fairly straight out. irridescence can be in either sex, although it is typically more pronounced. Hackle feathers are another rooster attribute but it is too difficult to tell from your photo what your bird has for sure. Lack of crowing does not necessarily mean anything. Right now, I have two four month old marans cockerels in my flock that includes two dominant roosters. Neither one has made a peep. Their brother, who is in a seperate building by himself, has been making those awful moans (preludes to a crow) for almost two weeks now. Sometimes, the presence of a dominant rooster will keep the young ones quiet until they are really ready to try and hold their own. Your bird also appears to have a pea comb and looks to be an Easter Egger cross to me. The shape of the body also says rooster. It is too elongated for a hen. If you could get a couple more photos that show the head and neck as well as the saddle area (right in front of the tail on the back) it would be much easier.
Thanks,
Richard