This has happened twice. About a month ago I thought I heard crowing, but when I looked outside I just saw my hens and by that time it sounded more like a complaining hen who was hoarse. This morning I heard it again and looked outside for maybe a wayward rooster. There was none. But one of my hens, (a white Easter Egger) was crowing. No doubt about it. It was clear and sharp. She's 2 1/2 and has been laying for 2 yrs now. So it's not like she's young and mistaken for a cockerel. She is high in the pecking order, but I'm not sure she is "the" alpha hen. I recently got rid of another alpha hen because at less than 2 yrs old she had stopped laying eggs. A thought crossed my mind that she stopped laying because she took over the roll of being the flock protector, more of the rooster's roll. Is that possible? Here's my little flock: Left to right: Patty (buff orphington), Shirley (Silver Wyandotte), Laverne (white Easter egger), Maxine (Araucauna), Thelma, Louise and Miney (all Easter eggers). Meeny is not shown. she's to the right of the picture. Miney is the crower.
As a general rule, no. Hens don't crow. There are some exceptions though when hens will crow. These hens often have masculine features like larger thicker combs, spurs, etc. These hens ussually don't lay any eggs. Some intresting research papers on this topic can be found HERE and HERE. You also can look into chimera.
