Grate the skin and flesh of the courgette and put into a colander; sprinkle it with salt, and set the colander on a plate so it can drain for 20 minutes.Squeeze the courgette with your hands to get as much liquid out as possible.In a frying pan, melt the butter and cook the onion for 8 minutes or until it turns translucent.Pre-heat the oven at 200 C / 400 F. In a bowl, put int the ricotta cheese, courgette, onion, herbs, egg, Parmesan, pepper and mix.With your fingers, gently make a pocket between the chicken skin and flesh a long both breasts and the thighs.Then, using a spoon, ease stuffing onto the pockets, gently pushing it as far down.Sprinkle the skin with oil, salt, and pepper.Roast the chicken for 1 hour or until the skin is golden. If it browns too much during roasting, cover it loosely with foil.Transfer the chicken to a platter, quarter it, and serve.