=General and special supplies.= From July, when the earliest farm chickens are large enough for roasting, until about the first of February, when the last of the late-hatched farm chickens disappear from the markets, there are nearly always enough very good roasting chickens in the general market receipts to supply the demand for that class and grade of poultry. Then for four or five months there are no fresh roasting chickens on the market except those grown especially for this trade. This line of poultry culture was developed first near Philadelphia, in southern New Jersey and eastern Pennsylvania, about forty years ago. The chickens were hatched with hens in the autumn and early winter, each grower having only a few hundred. They were sold not only in Philadelphia but in New York and Boston, and in smaller Eastern cities where there was a demand for them. They were, and still are, commonly known as Philadelphia chickens. [Illustration: Fig. 111. Massachusetts soft-roaster plant] =Large roaster plants.= After incubators came into common use, the production of Philadelphia chickens increased, but a more remarkable development of that line of production took place in Plymouth County, Massachusetts, just about the time the broiler craze started. The growing of winter chickens had been carried on to some extent in southern New England in the same way as in the vicinity of Philadelphia, but the local supply was small and irregular until artificial methods were adopted. Then, quite suddenly, the industry developed extensively in the vicinity of Norwell, Hanover, and Rockland. Its growth was remarkable, both because of the number of people who were successful on a comparatively large scale, and because it attracted almost no attention outside of this district until long after it had become a well-established local industry. [Illustration: Fig. 112. Incubator cellar] The methods of the roaster growers in this district are very intensive, but as originally developed their business was not a continuous line of intensive poultry culture, nor is it continuous now except in some cases. For many years after the business began, the growers bought the eggs that they incubated from farmers whose flocks were kept under good conditions and were strong and vigorous; but as the numbers engaged in growing winter chickens increased, the supply of eggs from the farms was not sufficient, and some of the roaster growers began to keep hens to supply a part of the eggs they used. Later some produced all the eggs for hatching that they needed for their own use, and a few sold to others also. This, however, can be done only by those having quite large farms. Some of the most successful growers have only a few acres of land and do not attempt to keep breeding fowls.