The leghorns are supposed to be really great layers, so you should be happy. Mine was a little skittish, but when you caught her, she would settle right down. I think it was just the idea of being caught! LOL!
Here is a link to a pic of my dark cornish when she was about your chick's age...
Yeah, I had a hard time when I was trying to ID my female leghorn. I was convinced she was some type of game bird! LOL! Here's a link to my pics, and you'll see she looks just like mine. She's the 3rd pic down.
https://www.backyardchickens.com/forum/viewtopic.php?id=158350
Shelly
The bottom pic looks like a dark cornish. It's hard to tell if it's a pea comb, but looks like it.
The one above it looks like a brown leghorn pullet.
Not sure about the first two pics.
Shelly