I did more research and found that heating a coop is NOT recommended at all!
It's not that black and white, although many like to still claim it is... In general with cold hearty, healthy, young-middle aged adult chickens heat is not recommend or advised in most instances... But, that doesn't cover all possibilities, If your birds are not cold hearty, not healthy ore are young or elderly heat very well might be a viable recommendation...
In that respect heating should be done with the up most care and safety, if your birds can peck at the heat source and damage it that is not a good thing, if you are using extension cords that is not a good thing and the list could go on, safety first... If one chooses to heat they need to focus on safety and why they want to heat, and then focus on the pros and cons of their decision and make an educated judgement call based on their individual circumstances...
I heat my coop, and it's the right choice for me based on several factors and my individual circumstances, the pros for me far outweigh the cons...