new pics of Dom pullets "keepers for now"

Thought I should take a couple new pics of my "keeper for now" flock. I have done two culls and I  have 20 left now out of 53.
I am trying to minimize the amount of birds I have to feed out over the summer so was able to sell my first two cuts of pullets to folks who wanted good layers.

Cant do the same in cockerels unfortunately other than the obvious leg color comb shape... I like to see their tails develop fully so I can see their top line before I choose. And sadly not many early markets for them so I  grow out for my own freezer
This bunch were hatched end of April

They look great! I really like their head shape, and the bright yellow legs.  And their feather quality looks so nice. Do Doms have the fast feathering gene?  

Ya, I'm trying to do the same, and only keep the best to grow out over the summer....but man these first culls hard! Doesn't help that I keep second guessing myself either...  

What age do you do your first major cull?