Black australorps

I got some chickens for $60, a rooster and 3 hens. I was told they are all black australorps and the breeder checked them in front of me before giving them to me. This one has brown feathers coming out of the neck, is it a black australorp? The hens are all back and greenish. They are not caged in there, they are free to roam but for some reason he likes staring at me from out of there 🤣