
UPDATE:
Thanks so much for all your input!! The girls are doing great. I have emptied everything out of the shed, so they have the entire 8x12 area for their house. The run I attached to the front of the shed is about 4x6, which I know is less than ideal, but I figure they are fine along with the large shed. As soon as I get all the debris and crap picked up from the numerous storms we have had, I will let them out to scratch in the yard periodically. I close the shed doors every night to keep out the cool drafts, and open them early every morning. I just placed a 2 bar perch made out of 2x4's in the shed, with a ramp, that stands about 3 feet tall. They are very curious about this, and I'm sure I will find more than one using it in the next few days. They all seem very content, and seem to enjoy and be very comfortable in their space. As soon as we get our roof replaced and all the other misc repairs done from the hail storm, we will build their permanent coop.
To address a few things mentioned and suggested by you all:
The shed does have a plywood floor kit installed, and the shed seems pretty well secured to the ground. It is set on a recycled asphalt pad, which is fairly difficult to get a shovel into, so I'm pretty sure the shed itself is as close as I'm gonna get to predator proof. So far, the nights have been pretty cool, so I keep the doors closed, and the girls seem to still have plenty of ventilation. But I will look into the vents mentioned above if they need to remain in the shed for longer than expected. The run is covered on all sides and on the roof with two layers of chicken wire, and an outer layer of 2x4 welded wire. I also screwed some wood lattice on the roof of the run for some added shade. I also placed cinder blocks on their sides around the entire perimeter of the run. I think I've taken a fair amount of precautions to keep my chicks safe and secure in their temp home.
p.s. I am so in love with my girls. They have just started exhibiting some sparring behaviors, which is a bit hilarious and frightening to watch at the same time. One of my RIR, named Aunt Francie, seems to be a bit more affectionate than the rest, and one of my BR, Margaret, has the most beautiful purring sound that she makes. Has anyone else noticed how soothing and calming they are to be around? I hope to figure out how to post pictures soon, so that I can show them off to everyone!!