I'm worried about the ventilation.. we are just using an added on section of our detached storage garage.. I'm not sure how to determine if it will be well ventilated, and if it's not how will I know and how would I fix it? I'm a huge worry wart. I've got 3 buff orpington, 3 cinnamon queen, and 4 barred rock. Would it be silly to keep a heat source in there even if it's not really needed?
in regards to ventilation, you want some vents up high ( the higher the better) as you don't want that winter wind blowing a draft in. ace hardware sells face plate vents( not what there called sorry but name escapes me) for something like 75 cents each i have 2. cut a hole slightly smaller then the face and 2 screws nice easy solution. also lot of info on this in the coop section for your worrying browsing needs XD (if your like me).
in regards to the heat source. with your chicks being young like my new additions its not a bad idea. ill be throwing a heat lamp in mine this winter. ill be using a ceramic bulb ( no light just heat , doesn't screw up their day/night cycle) with a thermostat hooked in so it will only kick in at a temp of my choosing.
the main reason i see people heating coops is either extreme colds or because you want more eggs in the winter. when a chicken has to use its caloric intake to keep warm thats what its body is gonna concentrate on.. warmth. but if you supplement it and keep it above just above freezing you'll get more eggs. dietary needs in winter aside I'm just speaking of the heat part