Breed ID

[KM2H]

Hello everyone,
I was fortunate enough to acquire 10 hens this past weekend. What I know about them is that they are 1-2 years old they came from cackle hatchery as a surprise box. The previous owner is not sure what most of them are so I will be posting here to see if you all can help me ID this girls. I want to know so I can learn from them as well. Thank you all for being so supportive and awesome.
She is the smallest of the 10 new girls, seems very lean, curious, nervous demeanor and my oldest rooster (barred rock) chases her like he doesn't like her

 

[NatJ]

That one looks like a Dark Cornish. If you pick up your chickens, I predict that one will be one of the heaviest. That breed tends to looks small because their feathers lie close to the body, instead of being very fluffy.

https://www.cacklehatchery.com/product/dark-cornish/

Or possibly one of these:
https://www.cacklehatchery.com/product/black-breasted-red-aseel-chicks/
https://www.cacklehatchery.com/product/dark-aseel-chicken/

my oldest rooster (barred rock) chases her like he doesn't like her

Can you get closer pictures of the back, slightly in front of the tail?
I'm thinking "she" might be a male, but I'm not entirely sure.

Dark Cornish roosters do not get the giant combs and big flowing tails that most other breeds of rooster do, so they can be a little confusing sometimes.

If the feathers on the back & sides, just in front of the tail, are skinny with pointy ends the chicken is male. If they are wide with rounded ends it is female.

(I feel like the head and the tail shape look male to me, but the coloring looks female, and I can't see the shape of the saddle feathers to be more sure on way or the other. If you've ever seen that bird crow or lay an egg, of course that settles the gender question.)

 

[KM2H]

I will get better pictures and maybe even a little video. Maybe that is why my older rooster is chasing it so aggressively.

 

[KM2H]

It definitely looks like the dark Cornish you linked and yes the tail pointing down is suspicious to me as well.

 

[KM2H]

A few other pictures, sorry if I repeated any, it's hard to tell with the phone format.

 

[NatJ]

A few other pictures

I still can't decide

I'll tag a few other people that are usually good at telling gender.
@The Moonshiner @Overo Mare
Any idea what gender OP's bird is?
(it's 1-2 years old, came from a Cackle Hatchery assortment, looks like Dark Cornish)

 

[Painted Calls]

Dark Cornish hen.

 

[KM2H]

Thank you. I did notice earlier that it squated to the ground when one of my roosters was doing its morning rounds but nothing else happened, I don't know if that helps or if it simply is a sign of submission
Even if it is a roo, I'll keep it around to see what happens but I'm definitely intrigued.

 

[KM2H]

Dark Cornish hen.

Thank you

 

[Painted Calls]

It's a hen. A rooster at this age would have male specific saddles.

It also sounds like you didn't quarantine or do a slow integration. If so, the no integration would be why she was getting chased.

In the future, make sure you quarantine new birds well away from your existing flock, for a minimum of 4 weeks.