Did damn near the same thing. Got a dog kennel and put two dog houses (large size) inside. Filled with bedding. They sleep inside the dog houses at night. I let them out for a couple of hours in the evening, while I keep watch.I got my last load of chicks going on 3 years ago. I only got 2 hatch babies last year. One was a rooster who hatched in my hand and he is very gentle.
After years of losing birds to varmints, this is what I did. I bought a 10x10 dog kernel, about 8 feet tall I think. I had old fencing I cut and put around the bottom of the kennel. Then used old fencing and snow fence around all that and over the top.
To make a house, I had an old picnic table that was broke up and some fence posts.
I dug 4 holes and set the posts in a rectangle. Then nailed the old picnic table boards over that. Old barn wood from the barn made a slant roof. We picked up some long plastic panels and nailed that all over the wood. Snow fence nailed around open small spots near roof. Old screen door, and board nailed for roost. Some old shop boxes for boxes.
The chickens watched us with excitement lol. The day we were done and let them in there (it's built into the kennel) was quite a party. They love it.
I took old wool junk blankets and wired them to sunny side inside. This keeps out sun and snow. They seem to really love their house and stay pretty comfy. They have the kennel yard and I let them out few hours at night.
Cheap and maybe not the best but it has worked good for 3 years.
I have since had to enlarge the original dog kennel.