I've had a small one very simialr that worked really well for raising some chicks and also as a hospital or broody breaking ward. It was sufficient short term. In all honesty, I wish I hadn't given it away. It was nove to have more options.
Most of the other advice is valid and with good wisdom.
Welcome to BYC! :frow
Only you can determine your level of risk. For me there are worse things than Marek's to be concerned about.
The following link has many answers to your questions..
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/