Elements of a Basic Coop

Great question!

I'll chime in with my little bit of knowledge but I can't wait to see what everyone else has to say.

Personally, predators were my number one priority when it came to the construction, so I built mine a few feet off the ground.

Ventilation is something to keep in mind, too, especially if you're going to be locking the flock up at night.

Sanitation seems to be really important, as the bedding you may or may not use could create debris and respiratory problems for the birds.

I needed to have a red heat lamp bulb that put out fairly low amounts of heat, mainly so that I could see inside of the coop when the sun went down to make sure everyone was inside. Then I could turn it off, or if it was going to be insanely cold I could leave the light on so they could have a little extra warmth.

A perch of some sort is a good thing, too. My Bantam and Silkie seem to be the only ones that use it at night, but they've definitely made it clear that they prefer having it over sleeping on the floor with the others.

I tried to make my coop in a way that would allow me to give the chickens comfort in winter and summer, so I built in a door on the back of the coop which has hardware cloth covering it to prevent predators from getting in. This way I can open it during any cold day to allow the wind to carry off any dust and kind of air out the thing, plus in the summer it will provide that extra bit of cool air at night to keep them comfortable.

The biggest problem I've had is with nearby coyotes. No attacks yet but simply hearing them so close at night has prompted me to set off small firecrackers on the perimeter of the property in order to scare them off. I've also made sure that my coop can actually be closed and double locked, both from a smart raccoon and a shady human. Each night I close up the coop, place a piece of wood or curved rebar into the handles on the doors (to keep away smart raccoons) and physically lock the coop (to keep away people). I placed the coop in a repurposed dog kennel, so I lock that up as well. Then that whole enclosure is inside of a large fenced area which I again secure from predators.

 

Wow, I should have been more brief and not rambled so much.

To answer your question more clearly, a coop should be large enough to house the chickens and you might consider adding a "run" to it, which would just be an area they could roam around in during the day. You would probably want to fence that part in unless you can keep an eye on them all day.

It can be done cheaply with materials you can find anywhere, used or new.

Used pallets behind stores work well. Since chicken wire can be pricey, you can find other materials that might suit your budget a little better, like metal screen door fabric, or some of that plastic chicken coop stuff, looks like road construction material to me.

And make sure the chickens have very easy access in and out of the coop itself, like a ramp on a comfy incline with steps or some sort of material they don't slip on.