Well, they could be Australorps OR Jersey Giants.
The one in your hand has a yellow tinge to the top of his feet, and I'm wondering if he doesn't have a yellow tinge on the bottom.
The yellow on the bottom means it's a Jersey Giant. White/pink on the bottom is Black Australorp. (Most hatchery Jersey Giants don't have the yellow skin on the bottom. So it's not always true.)
I do think the rest of your Australorps ARE Australorps! lol You just got "lucky" with the Black Sex-Link females! They usually only throw in the males as "packing peanuts."
The one in your hand has a yellow tinge to the top of his feet, and I'm wondering if he doesn't have a yellow tinge on the bottom.
The yellow on the bottom means it's a Jersey Giant. White/pink on the bottom is Black Australorp. (Most hatchery Jersey Giants don't have the yellow skin on the bottom. So it's not always true.)
I do think the rest of your Australorps ARE Australorps! lol You just got "lucky" with the Black Sex-Link females! They usually only throw in the males as "packing peanuts."