We do have plans for a chain link fence around their entire area.  In fact we have already bought the material and started digging the holes.  The coop does still need to be built pretty well as we have lots of different predators.  I can't remember what they are called...those little ferret things? We've got lots of those!  Lots and lots of Raccoons, Fox, Skunk, Fox, Dogs, Cats.  You name it and we probably have them!  We have had them get through chain link so I just want to make sure they will be completely safe at night while locked in there.  No big deal.  We decided to just build it a little smaller than I had hoped for.  There will still be more than enough room for the girls I have now, and later down the road we will build the addition to it like I said before.
 
The pallet house sounds interesting.  I know I can get a bunch of pallets for free!  Can you send me a link with some information?  Or maybe if someone who has made one can give me some advise?