When the hay has been harvested and the corn has grown tall, a part of the young chickens may be removed from the land where they were started, and the coops placed where they can forage on mowing lands, in cornfields, and wherever they can go without damage to a growing crop. As they become too crowded in the small coops, the cockerels are sold and, if there are still too many birds in a coop, a few pullets are taken from each of the overcrowded coops and new colonies are started, so far from their old associates that they will not find their way back. [Illustration: Fig. 107. Colony house for growing chicks, at Macdonald College. (Photograph from the college)] In the early fall as many of the oldest hens are sold as is necessary to vacate the houses needed for the pullets reared that season. Then the houses are thoroughly cleaned. (They may not have been cleaned before for six months or a year.) If a house is to be moved to a new location, the change is usually made at this time. One or two cartloads of clean sand are put into each house, to make the floor higher than the ground outside and to provide an absorbent for the droppings which are allowed to accumulate. When they are brought to the house, which will probably be their home as long as they live, the pullets are confined to the house, or a small temporary yard is attached to it, so that they cannot wander away. After a few days of confinement they accept the new home as their headquarters. =Adaptability of the colony system.= The colony system as developed in Rhode Island attracted little attention elsewhere until very recent years. Since about 1900 many descriptions of it have been published, and numerous efforts have been made to adapt features of this system to operations in other localities. The principal obstacles to this are snow and predacious animals. Where snow lies deep for months it is not practical to keep fowls in widely distributed flocks in winter. In some places the plan of distributing the houses in summer and parking them (that is, placing them close together in a regular order) in winter has worked very well. Where wild animals are numerous, colony methods cannot be extensively applied, but on most farms a limited application of the system will greatly increase the amount of poultry that can profitably be kept. In England many farmers use smaller colony houses than those in use in Rhode Island, and move them often, not letting a house stand in the same spot long enough to kill the grass. Some of the houses used in this way are provided with small wheels. The advantage of moving houses often is greatest when the fowls are on good arable land, upon which there are, or will be, crops that can utilize the manure which the birds leave on the land. If the houses are moved methodically, the fertilizer will be evenly distributed. INTENSIVE POULTRY FARMS