Why won't my chickens roost/perch?

[Desirai]

My chickens are 3 months old.

I installed 3 perches in their coop.

One at 4ft (level with the nestboxes but on the opposite side of the coop)
The second right above at 6 ft, and the 3rd right above that at 8ft.

Are they too high?

They won't get in nestboxes either. All my chickens sleep on the floor of the coop in a corner right against the chicken door.

 

[Den in Penn]

If they were raised in the brooder with out perches they may not yet have figured out what roosts are for. If the roosts are a reached by a straight jump up only then they may be to high for easy use.
Chickens do nest on the ground. I don't think they are comfortable nesting high. My lower row of boxes is at 18 inches the second level is about 30, more eggs are laid in the lower row. By the way the nest boxes should be lower than the roosts so they don't use them to sleep in.

 

[Mac in Wisco]

Four feet isn't too high for most breeds. If you've just installed them they may be leery of them for a while. You can train them to roost there at night by placing them on the perches at dusk for a week or two. They do need a clear flight path down though. In smaller coops with high perches you'll find that although they find their way up there without too much trouble, they may fly into the walls trying to get down.

They won't take much interest in nest boxes until they are getting ready to lay. Four feet seems pretty high for nest boxes. In my experience two feet, give or take a little, works well.