The heat plate is the right height and is nice and warm.I shove them under (gently) like a momma hen gathering them up and they go under and fall asleep. I would check the height after they are under. It has to be low enough that they have to bend over a little to get under there. If it isn't they will be too cold when they lay down.
2 chicks look "out of it" and wobbly.
The other ones are thriving and running around luke normal.