Hi there.
Try sitting at their level or raising them to yours.. and reach from the side and down low just like when you are feeding them. In this manner it is not the same as predator coming from above. Also, stay there a while and
let them come to you. Let them inspect your hands, maybe peck a little (inspection not aggression). Polished fingernails are hit! I sit in the ground in a fresh grass patch and put the meal worms on my pant leg. Even my friendliest bird that follows relentlessly and rides my shoulder up and down the ladder or whatever I am doing... If I just rapidly approach she gets on the run and prey instinct takes over and she avoids me. So I guess I'm kinda saying playing coy seems to work well with shy animals
Another secret... handle them once the are settled in to roost in the evening if they are doing that. I can usually pet their chest more easily. When you pick them up, hold their wings to their body so they aren't flapping and freaking everyone out. However be aware that pin feathers can be kinda painful and if they are getting squeezed, handling may be uncomfortable and send the wrong signal. Gently return them to roost and do this one by one, nightly. Stay calm yourself, talk gently. See their individual personalities. NEVER put them down when they are freaked out. Wait for calm and set them down gently. These tips will work for some birds and not others. But in my experience they all calm down a lot once mature.
One of the times I handle them might be on daily trips to the outside and back in again at night, for a period of time before they are moved out full time. They get used to being handled, they know this is normal and they go with the flow... Mostly. I see you say they're already on the coop, and that's awesome!
I tend to go for the flightiest bird first as their fear factor radiates to others. I thought leghorn were bad until I got white faced black Spanish, them birds can scream!
It just takes persistence, patience. You already have the mother load of all chicken treats in meal worms. Try switching it up a little and pique their curiosity. They all seem to respond of I use a higher pitched voice and quickly call in the same manner of a broody... Look babe, look!
Hope this helps give ya some ideas at least.
