can i separate my chicks if they’re growing at different paces?

I have seven tricks that were born in the middle of March and I have two silkies among them that were born March 28 and I got them a week later am I able to separate my Easter Eggers and maybe even one of my barred rock or brown leghorn chick if they have are already fully feathered while the other ones are still fluffy. it feels like the bigger chicks are getting too big to the point they are stepping on the other ones when I come in to change their water or give them worm treats. i don’t want my chickens to feel cramp. what is the best option. i’ve been told to not separate them or else they will fight when i add them together again but ive also been told to put them in the outside coop once they are feathered. what do i do?