I am a novice, but that was the first thing I thought about when i saw the pictures...and I do know that White Leghorns are commonly carried at TSC during chick days because many folks like a white egg. I heard someone say that trying to catch a White Leghorn is like unto an Olympic sport because they are so flighty.
Your boys just appear to me that they aren't going to be very meaty, but that could just be their age.
I have a White Rock hen and she isn't flighty. I have some White Rock cockerels coming Monday that I am planning to caponize in a few weeks, which will be my first experience with the malesof that breed.
Perhaps some other folks can chime in regarding the breed of your "Three Amigos"