Thanks for the replies, and for the compliment, aartNow I just have to figure out how to do the chickie door(s)... I can easily cut openings in the hardware cloth but I'm not sure how to do it in a way that allows me to close them again if necessary, and to avoid sharp edges. Suggestions are welcome, lol! Plus I need to pick up chicken wire and get busy putting that around the pen. The fence is 5+ feet tall; would 3 foot wire be enough, do you think? I plan on using 1" mesh.
Take two thin pieces of plywood, if you want these to be permanent, or cut out two pieces of thick cardboard. Fasten hinges on the two pieces so they work together. Cut an oval or rectangular 5 x 7 inch opening in one. then secure the two over your hole in the hardware cloth so it makes a nicely framed opening. Fasten the solid "cover" open until you need to drop it down over the hole to contain the chicks. See my article linked below on brooding outdoors for pictures of these so you can better get the idea.