Shipping container winter coop

I plan on raising chickens on pasture in the spring , summer and fall in a old pig trailer that can be moved around the farm.  I need a winter coop though.  
I have coveted those coverall structures that use old shipping containers as anchors for the storage  and cover they provide.  Do you think converting the south facing container into a chicken coop would make a good winter home?  I would add a door and some windows on the south side for access and light as well as some holes for ventilation on the roof line.  I would also paint the south side black to maximize solar temp gain.

I stress this a winter only coop.  I would think  it would get way to hot in summer.  Are there any pitfalls that I am just not seeing?

Thank you.

The general complaints I hear about metal buildings include temperature swings and dampness due to water condensing on the metal.

If you don't already own the container, I would lean towards building with wood and making the inside as smooth as possible for easy cleaning. We had issues in our wooden coop where mites got between the plywood sheets into the wall cavities (we didn't build this - it was on the land when we bought). I spent several days carefully caulking every join and the problem was reduced to 1 area by a window that I'd missed.

I also highly recommend making the perches and nest boxes removable so they can be cleaned easily and ideally left in the sun for a day or so as the sun can sterilize things well.

I don't think conex boxes unmodified would suit the needs of a flock.

My biggest concern for the shipping container is to ensure that it has proper ventilation where it matters. You want the hens to be able to roost but have ventilation high enough so they are not caught in a draft. You want to avoid ammonia buildup during the winter season especially if they are not going outside far due to the winter precipitation.

I would recommend if you were going to use a pod to also consider how you will protect the floor of the unit. Chicken excrement could encourage rusting of metal if it comes in contact with the shipping container. The effects would take a while to be seen but it EVENTUALLY would become apparent.

Put it on gravel, add good venting, and make it easy to get the poop out.  The metal reflects radiant heat.  So with good air flow, it wont get hotter than the outside.  And if you have a heat source inside, it will contain the radiant part of the heat when it’s cold outside.  

Steel containers won't breath.  If you are buying suggest simply building a wood building and insulating it.

Thank you for your replies . I think the consensus is that that this is a bad idea and that I should build with wood instead. That is what I will do.

Once again Permies to the rescue!