How to Make It
In a large pot, combine the water with the salt, sugar, peppercorns, bay leaves and juniper berries. Bring to a simmer to dissolve the salt. Transfer the brine to a very large bowl and add the ice. Let cool to room temperature, then refrigerate the brine until chilled. Put the chickens in the brine, breast side down, and refrigerate for 4 hours.
Remove the chickens from the brine and pat dry with paper towels. Put the chickens on a large rimmed baking sheet and sprinkle all over with the Toasted Spice Rub. Set the chickens breast side up and tie the legs together with kitchen twine. Refrigerate the chickens, uncovered, for at least 4 hours or overnight. Bring the chickens to room temperature before roasting.
Preheat the oven to 450°. Brush the chickens with the melted butter and roast in the upper third of the oven for 45 minutes. Reduce the oven temperature to 350° and roast the chickens for 30 minutes longer, or until an instant-read thermometer registers 155° when inserted in the inner thigh. Let the chickens come to room temperature. Carve each one into 8 pieces, transfer to a plate and serve with the Raisin and Pine Nut Agrodolce.