I am asking for advice and ideas. I just can not get electricity to the coop, but i want them to be comfortable this winter. Also I want egg production not to decline to much due to cold and lack of light.
I am planning to buy a solar powered light from Sam's Club. They have them here right now for $35, which is for the light and solar panel.
As far as heat goes, I wouldn't add that. I think it would mess them up, going from warm to cold all day long. As long as you make sure your coop is dry and draft free (those two things are the most important), they will get along okay. We had a week of below freezing temps here this past winter and all of my birds did just fine.
It is easy to buy a battery-powered shed light for you to turn on if you have to work out there after dark (although personally I think a headlamp is often more convenient).
Because there is no convenient way to put it on a timer, though, that will not work so well if you really want to add light in hopes of increasing winter laying (which may or may not make any difference *to your particular birds* and which there are debatable pros and cons of). The easiest solution for that is probably to get one or several of the cheapie solar-powered yard lights, like to light a path, and set them up so the panel is outside of the coop facing south but the lightbulb is inside the coop. If you are living right, you will find that the few pathetic hours of post-sunset light they provide are just right to give you 14+ hrs of "daylength". It may require some fiddling, but is otherwise straightforward
But, you are in Mississippi? That;s pretty far south - how short do your winter days even GET? Surely there is not more than a month or six weeks when you would even *possibly* want extra light on the basis of hoping to increase laying?
As far as heat, a) you do NOT need winter heat in mississippi
and b) you are not going to get it from a battery setup anyhow, not unless you invest many thousands of dollars in a serious solar setup which would just be silly. You really, really do not need it anyhow though
I have not found an economical solar solution for supplying serious extra light for when they need daylight or heat. I finally gave up and bought the wiring and ran it about 140' to my coop. One single strand of 18 gage wire 250' long cost about $59 and will carry enough current for a timer/light and my electric fence. Most small solar lights just don't carry enough watts to give sufficient light for 2 extra hours a day and certainly not enough solar power for heat without spending thousands of dollars.
With somewhat mild winders I will probably use a very low watt heater or lamp to break the chill during the coldest part of winter.