Sorry I haven’t answer this; I had to think about it! With my first four, I was not sure who was the alpha for a long time. I think it was Margo, BUT Bagheera pecked her lower back feathers and Margo submitted.
I think it was subtle and came down to who had their pick of roosting spot, who backed down to whom with treats, etc.
Now it’s clearly Bridge, but she’s the oldest, meaning, she has been there from day 1 for all the others. She rarely pecks anyone. She just lifts her head in a certain way with a stern voice.
The others squabble for position. I see Flo as an alpha in the making. She is VERY assertive (and has her head plucked almost bare to prove it!

) She will challenge anyone, including Bridge, bit then gets put in her place.
Buttercup seems to be the #2 (enforcer) and is a bit of a jerk to the others.
So, here is an interesting observation. I’m curious as to what
@Shadrach thinks, since he’s not as much into the cuddly lap pet thing for his birds. ALL of my highest ranked birds gave been affectionate lap sitters. I’m not sure what to make of that.