In Europe, where fowls are systematically fattened for market, they are fed on barley and oat meal, rice, Indian meal cooked and wet with milk, and sometimes mixed while hot with beef or mutton tallow. Chopped carrots and parsley roots and leaves, cabbages, celery leaves, etc., are given to them now and then, and regular doses of pepper corns or cayenne pepper to stimulate the appetite. Special pains are taken, by a process of cramming, to hasten the fattening, and two or at most three weeks are sufficient for this.
Fattening fowls ought not to have a large run, but should have a chance to stand in the sunshine, to dust themselves, and to scratch in the ground. Pure water must always be furnished, and pulverized charcoal should be mixed with their soft feed every two or three days, enough to blacken it partially. This charcoal ought to be of all sizes, from that of a kernel of wheat to dust. It is good for the digestion, prevents disease, and indirectly promotes fattening. The difference between a lot of fowls furnished with this charcoal and one deprived of it will be very striking.
Indian meal scalded is one of the best kinds of soft feeding, and it is better with small potatoes boiled and mashed while hot and mixed with it, together with some bran or shorts. Some mutton tallow or other cheap fat will add greatly to its fattening quality. Pork-scrap cake, soaked and pounded up, may be fed with it, but not too freely, no more than a pound to a dozen fowls every two or three days. Green cabbage leaves, beets, etc., are greatly relished.
Fowls put up to feed for market ought to be ready in three or four weeks in the early fall. It will take longer after cold weather sets in. If they are deprived of a free run they must be furnished with gravel every few days. A little salt mixed with the food now and then will improve it. A small quantity of it mixed with the soft food will usually stop any inclination to pluck each other’s feathers.
[Thomas’s Farmer's Almanac]