I'm no expert but that does sound a little high. The perch in my coop is just two inches of the floor, with a layer of straw underneath..it helps keep them warm in cold weather and makes cleaning a ton easier! Hope that helps.
Same here. My perch is about 3 inches up and then they are tiered up to about 2 feet.
If they are battery hens they probably just don't get the concept anyway. My hens weren't battery but had been kept in cramped conditions. I had made lovely perches for them and had left an old chair in the shed just in case they needed more space. All six huddled in the space under the chair for the first 2 weeks!! Give them time and they should get the hang of it. I'd probably lower the perch though just in case it is too high.
I can only speak for myself but I notice that my silkie hen would have difficulty getting up to a perch that was even chicken height from the floor as she can't fly at all but all my other hens (sussex and sussex x RIR) would get on it no problem so it probable depends on the breed too.
My chooks have two perches one around 3" above straw level and one about 1.5ft above straw level they nearly always use the top one, no idea how they get up there though always in bed early! Your chooks if they are exbattery may not have had a perch and therefore may nor know what its for, give them a bit of time.
"no-one can make you feel inferior without your permission"
My perch is about 35cm off the floor and the girls have no probs hopping up and down off there. In fact they do it often when they are playing musical perches before going to sleep - constant changing of positions - I want to be by the wall, no budge over, I want to be in the middle.....
My perch is about 4ft off the floor although there is a shelf for them to jump up onto first. They tend to ignore this and fly straight up onto the perch. Some breeds can fly really well and some just can't get off the ground. My black pekin bantams can't jump more than a couple of inches but my neighbours light brown bantam (can't remember the breed) flew straight up on my roof just before Christmas and then soared off down the road with the doves. She soon came back though when she got hungry.