In a bowl, mix together the Chef Merito® Lime Juice, Chef Merito® Garlic Salt, Chef Merito® Chicken Seasoning, and olive oil.
Place two hens in a zip-top bag and add half of the marinade. Repeat for the other two hens. Marinate in the refrigerator for at least 4 hours, preferably overnight.
Preheat the oven to 425°F.
Place the hens and their marinade in a large casserole dish. Add water and arrange the onion slices around the Cornish game hens.
Roast for 20 minutes, then reduce the heat to 375°F and roast for 1 hour 15 minutes to 1 hour 30 minutes, until golden brown.
Remove from the oven and let rest for 20 minutes while covered.