Dissolve the kosher salt in the hot water; then add the ice and cold water to chill mixture. Add the lemons, limes and fresh herbs to the brine. Make sure to put it in a container large enough to hold two chickens.
Add the chickens and put the container in the refrigerator. The chickens should sit in the brine for at least 8 hours but overnight works best.
After the brine step is complete, preheat the oven to 350 degrees F, remove the chickens from the brine and discard the brine. Dry the chickens with a disposable towel and lightly oil skin. season with salt and pepper.
Place the chickens in a roasting pan elevated on a rack.
Roast for 20 minutes per pound based on the weight of the chickens, plus 15 minutes, or until the thermometer inserted in the thickest part of the chicken but not touching the bone reads 170 degrees.