Retirement farms in Virginia/MD and Florida

As part of our wills we need to have a retirement location for our 4 horses, ages 18 to 14. We want to kindest and best for them, so please let me know your recommendations. We do have two horses that could go into retirement in the next year due to injuries they incurred before coming to us. So, I am looking for some location sooner than later. Thank you so very much.

Sloane Coles farm in VA does retirement.

What do they need? Grassy field, dry lots? Turnout 24/7, stalls?