Clean the pigeons well. Rinse, drain away the water and pat dry with paper towel. Lightly season the insides of the pigeon with salt and pepper, then the outsides. Finely chop up six of the sage leaves. Remove the rosemary from its stem and chop up finely. Mix the sausage meat together with the chopped sage and rosemary, and divide this between the pigeons, stuffing it into their cavity.
Put the olive oil, garlic cloves and remaining sage leaves into a saucepan that will accommodate the pigeons snugly, and heat up. Add the pigeons and on a medium heat, brown them all over. It should take about 10 minutes on each side. Add the wine, and continue cooking uncovered until some of it has evaporated. Pour in the hot stock or water, lower the heat, cover the pan, and continue cooking for another 30-40 minutes, until the pigeon is cooked through and tender. Turn the pigeons over a couple of times during the cooking process to ensure they cook evenly. Make sure there is a little sauce in the pan, if not add a bit more water or stock. Add the olives and simmer for another 5 minutes.
Meanwhile, grill (broil) or toast the bread on both sides and put onto individual serving plates. Transfer the pigeons to a cutting board and divide each one lengthways in half. Put a pigeon half over each piece of grilled bread, spoon over the sauce with a few olives and serve immediately.