What breed are these chicks?

[Siddiqui]

Hey guys, I bought these chicks from Tractor Supply about 3 weeks ago and I was told they're bantams, and that the brown one is an Ameraucana. I know now that its actually an Easter Egger but I'm still confused as to what the 2 yellow/white ones are. They had yellow down a couple weeks ago, but since then they've developed white wing and tail feathers. I added some pictures for reference!

 

[AltonaAcres]

Either Cornish X or white rock

 

[Pretty Birds]

They look like Cornish Crosses.

 

[Siddiqui]

I was hoping they would be white leghorns or white plymouth rock because they don't seem to be growing as fast as a cornish cross would

 

[keesmom]

I was hoping they would be white leghorns or white plymouth rock because they don't seem to be growing as fast as a cornish cross would

At 3 weeks they are still the size of the EE? If so they aren't meaties. My guess would be white Rocks.