Rooster insists on sleeping on top of the coop

[berferd]

We keep chickens to eat the spiders and ticks around the outside of our house. We have 3 hens and 1 rooster (Rhode Island Reds). I have a very strong chicken tractor pen, and the coop is inside that, so all the chickens are safe at night. But Sam, the 3 year old rooster insists on sleeping on the roof of the coop. He is safe but he gets so cold in the winter. We gave him a heated perch, and that helps, but he gets frostbite on his comb.
I just installed a Ceramic Heat Emitter, 75W Reptile Heat Lamp, over his perch, hooked up up through a dawn-to-dusk, and temperature switches. It will only run after dark, and only if it gets down to 32 F degrees.

Asking here for ideas on how to deal with this dumb bird?

 

[nuthatched]

There's not enough room for them all in the coop, so he's opting to sleep outside. Its also his #1 instinct is to roost as high as possible.

 

[berferd]

I think it is more a flock dynamic. There is plenty of room in the coop.
I guess I need to explain the flock.
Sam and Queen are what is left from a Tractor Supply purchase of 5 chicks, 2 roosters and 3 hens. The one rooster had to be put down as he was violent and abusive to the hens. Sam took over the rooster job magnificently.
And the two younger hens, Dumpling and Ramen are from a batch of pullets purchased a year later. So the flock is split into 2 factions, the older and younger.
Queen always sleeps with Sam (until it get too cold) on the roof with him. So in the coop it is just 2 chickens, the 2 younger hens Dumpling and Ramen. I have a second pen, with a second coop that I used to raise the younger chickens before introducing them to the main flock. But even when Ramen and Dumpling were in the other coop, Sam still slept on top of the main coop. Chicken Machismo I guess :-D
I suppose I could try to break this behavior and make it a habit of picking him up and putting him in the coop at night. But he really hates that.

Update: First night with the heater thing, Queen seemed to enjoy it, Sam didn't like the "new scary thing", so he slept flat on the roof.

 

[Yardmom]

This is instinct to sleep as high up as possible. My daughter takes the birds off the top of the pen every night (not predator proof on top for us.) and I can't climb up like she can. Unfortunately we have birds that have been doing it for years, and moving them doesn't change what they do the next night.