Putting a monitor would be fine. I would look online for a prefab coop and hire someone to put it together for you. You should be feeding her proper chicken feed and oyster and grit sides, you can buy these online or at some pet stores and all feed stores. I don't worry about cats, my girls free range my yard and kitty next door comes and hangs and the girls are about the same size, but there's 4. Raccoons are nasty tho, so definitely need to make sure your coop is proofed. There are great threads on here regarding everything and all things chickens, even coop design. Get your coop set up then go find another bird or 2. You will be so glad you did!
https://www.backyardchickens.com/articles/category/coops.12/ for ideas, you could also look on Craigslist to see if anyone is giving away or selling a coop that would work for you, maybe even have it delivered