Getting a chicken from another flock is a good idea, but good biosecurity requires a 30-day quarantine period. By that time, chicks would be way old enough to integrate, and she would have had the company of them, even in a see-don't-touch setup.You can maybe check Craigslist or Facebook groups to see if you can get another similar age chicken, or maybe rent one out.
If you did do this - Make sure you go to pick the chicken up so you can see the condition of the coop and other chickens. It is a risk with the chicken having some kind of a disease, but there are a lot of very good keepers out there who raise healthy flocks.