The phrase "exercise yard" refers to an outdoor area, usually in a prison, where prisoners can go outdoors to exercise, walk around, or get fresh air. Full definition
Your dog will be able to run in our fenced in exercise yard and will be given a treat before he / she goes to bed in a climate controlled facility. (midwestdogcenter.com)
He enjoys spending time outside in the fenced exercise yards and playing with his toys. (hhaf.org)
When not in use for such purposes, the area will be used for temporary volunteer housing, special events, adoption days, and dog exercise yards. (americanhumane.org)