For some seventy or eighty years, but more especially for the last thirty or forty years, the most conspicuous phase of the poultry industry in America has been the widespread and continuous movement to develop large plants of this character. There has been no time, for a quarter of a century, when poultry plants of this kind, which to the uninitiated appeared to be highly profitable, have not been numerous. The owners of many of these plants have claimed that they were making very large profits, and their claims have led others to engage in the business, following in every detail the methods in use on some large plant which they suppose is very successful. So, while well-informed poultry keepers know that these methods are not practical on a large scale, except in a few limited lines of production, there is in the business a constant succession of newcomers who try to operate egg farms and breeding farms and combinations of various lines by methods that are not suited to their purpose. [Illustration: Fig. 110. Interior of a compartment in commercial poultry house, United States Government farm, Beltsville, Maryland. (Photograph from Bureau of Animal Industry)] =Common type of intensive poultry farm.= The ordinary special poultry farm is a run-down farm upon which have been erected the buildings necessary for the accommodation of from four or five hundred to two or three thousand fowls kept in comparatively small yards. The buildings are nearly always neat and substantial, the fences strong and durable. The arrangement of the plant is orderly, and, when well stocked with fowls and kept clean, it presents a most attractive appearance. The houses and yards for adult stock, the incubator cellar and the brooder houses, the barns and sheds, and the dwelling of the owner or manager occupy but a very small part of the farm--usually from one to three acres. The young chickens are grown year after year on the nearest land not occupied by the permanent buildings and yards. In most cases the land is so heavily stocked with them that they secure almost nothing by foraging.