[Stereo]

I use the Mole Valley ones and usually find it's a few days for them to get used to it. I put a stone on the plate for a few days so there is no noise or movement and the food is in view. Once they are used to eating from it I take the stone off and leave them too it. Usually one or 2 will work it out. Sometimes I put the stone on again for a couple hours in the mornings so that any really nervous ones get a feed.

Worst ones I had were the Leghorns who would explode into the air every time another bird touched the feeder. But there are fine with it now. I would recommend more than one though in different locations as the bullies will sometimes guard them as mentioned.

[Ghdp]

An up-date.
Mrs Ghdp hit on the idea of dropping meal worms in the groove just behind the closed lid. The girls soon got into the idea of stepping onto the plate to get to them and, as the lid opened as a consequence, reaching in underneath the lid to get the treat.
Not entirely confident as a flock  yet ( and our leghorn cross is certainly the most flighty Stereo) but they are getting there. Certainly not a three week training exercise as suggested by the manufacturers in our case but once it is accepted it will make life easier for us!

[Bionic]

It sounds as if the girls are well on their way now Ghdp