I am a first-time chicken owner and have a flock of five 5mo old hens that I got all at the same time as chicks this spring. They are all laying except one, who is also slightly smaller than the others. She has been getting severely picked on by her flock mates (mostly by one hen, but sometimes...
Looks like a hen to my inexperienced eye, but has been making suspicious crowing sounds... I only have one of this breed so no point of reference. It is the all black chicken in the photos!