Seventeen is the regulation number of pheasant eggs to be put beneath each hen, and seventeen chicks are put with each hen in the coops in the rearing-field. The most motherly hens are selected for service on the rearing-field. Less careful mothers are turned out when they have hatched the eggs, or, if they are willing, are supplied with another clutch. A hen that will hatch several clutches is too useful to be honoured with the task of bringing up a brood, and must be content to play the part of a living incubator. The keeper knows his hens through and through--and he can tell when a hen has chicks without seeing them, by the bristling of her feathers at his approach, and her instinctive clucking. An incubator helps the keeper to cope with the whims and frailties of broody hens. It is always ready to receive those unexpected eggs which may be brought to his cottage at any moment, as when sitting birds are disturbed by sheep or cut out in the mowing grass. And it is ready to take charge of the eggs abandoned by a fowl, or the chipped eggs of a foster-mother which shows an inclination to crush the chicks as hatched. Yet it will be long before it ousts the broody barn-door hen from the rearing-field. In the days before incubators, keepers who found themselves with more eggs than hens were forced to strange shifts. One keeper saved the situation with the help of ducks. Wild duck nested in numbers on an island in a lake, and one spring day he took six hundred pheasants' eggs to the island, exchanging them for the eggs of the sitting ducks. The ducks proved excellent sitters, but as his hens became available he would punt to the island to relieve the ducks of their charge. Pheasants were more prized in those days than wild duck. Such a sacrifice of duck for pheasants would be saved to-day by the ever-ready incubator. While pheasant-rearing is chiefly a matter of skill, luck plays a part in success, and of course a light warm soil, a good situation, a good supply of natural food, and good weather make all the difference. If eighty eggs hatch out in a hundred this is considered good; if less than seventy hatch, this is bad. A keeper may congratulate himself if he turns a thousand pheasants into covert from fifteen hundred eggs set; anything below one bird turned into covert from two eggs is considered a poor result. Keepers believe that chicks cannot be hatched too late in May or too early in June.