Solar and wind are exciting technologies that get better all the time.
Edited by ChickenCanoe - 12/28/11 at 11:25am
This is just my two cents worth as a former industrial electrician, power transmission and automation engineer and most recently, project manager for a solar and wind power company.
I only noted one feather ruffler.
I believe jerryb and Bear Foot to be good readers.
jerryb gave good information to begin your calculations and Bear Foot Farm correctly discussed AVERAGE solar energy per day and the added cost of inverters, controllers and batteries.
Solar day length isn't when the sun shines but when it strikes the panel within tight angles. That can be increased with solar trackers which adds more cost. Everyone has cloudy days that figure into total power available for charging. You get very little energy on a cloudy day.
Creating heat is the biggest energy hog so battery banks would have to be huge. Even larger if you don't want your chicks to chill after 2 days of rain.
You can eliminate the inverter but then you'd have to go with 24 volt heaters(slightly more cost than heat lamps).
Wind is a good supplement to solar because when you don't have sun, you often have wind. It is still very expensive.
The most cost effective use of sun for energy is solar thermal(hot air) and solar hot water. Since the thermal is only during the day that leaves you with a super insulated solar hot water tank and you could use that hot water to keep a brooder warm.
I'll be using solar for lighting in the coops but using it for any type of heat source is beyond my wallet at this point. I will be building my own panels and will save money doing so.
Another consideration for running electric is the voltage drop. The OP noted the brooder shed was 150 yards away. I haven't put pen to paper on it but I would guess at that distance you would need #8 or possibly larger wire to run that far. Has anyone priced wire lately? If you did all the work yourself, I'm guessing wire and material could be as high as $1,000. (still cheaper than the solar) More than likely, local code would require 12" minimum burial. If you don't have a trencher, that's a lot of digging.
I just ran electric to one of my new coops 100' from the closest building and dug it by hand - tree roots were a bear. I ran #10 in 1 inch conduit. I went that route because I already had the wire and wanted room to run additional cable for automation later. At that distance it would run a couple ceramic heaters, a small motor for automatic doors and all the flourescent/LED lighting I need.
In the final analysis, I suggest you build a small shed for brooding near your electric source for the brief 4 - 6 week periods when you need to run a couple heat lamps.
There is just no way, in the forseeable future, to generate heat in an isolated outbuilding with solar that makes financial sense for chickens.
Another good option is broodies. No electricity needed.