infected, the best possible procedure is to isolate and slaughter the infected adults and thus prevent future outbreaks. Thorough disinfection of brooders and incubators will prevent the transmission of infection through future hatches. The organisms are easily destroyed by dilute acids; hence the feeding of sour milk to infected flocks for the first few days is advisable. Every poultryman hatching chicks should make all possible effort to understand and prevent this disease, since it causes much loss.

Hardening Process.-In order to prepare the chicks for removal to the range, after the second week, a hardening process should be begun. This consists in the gradual lowering of the temperature, with the idea of dispensing entirely with artificial heat in from three to six weeks, according to the weather. The best method is gradually to reduce the artificial heat until it can be entirely given up, then raise the hover a little at a time until it is safe to remove it and replace it with muslin-covered frames hung to the hover wall; these can be raised in front a little more each night until the chicks can do without them. It is impracticable to take chicks from a warm brooder house and put them in a colony house unless they are gradually accustomed to the change. The idea should be to get them on the range as early as possible. After they are four weeks old, the sooner they are out on the ground in a cool atmosphere, and have large, wellventilated quarters with free range and plenty of green feed, the faster they will grow, and the more hardy and vigorous they will be at maturity.

Systems of Heating Brooder Houses.-There are two general systems of heating large brooder houses, namely, hot water and steam. Hot water is the more generally used. It maintains a more uniform temperature with less variation either way, and the heat is retained much longer than by steam. The brooder house is a compact building requiring no complicated system of piping which would make steam necessary.

The Heating Plant. In a long brooder house the boiler should be centrally located. It is poor policy to run the brooder pipes more than one hundred feet, as the loss of heat is great, the pipes become cool, and it is impossible to maintain an even temperature in all the hovers. With the hot-water system the heater should be located in a pit, in order to provide for the circulation and return of the cold water. Whatever type be selected, the heating plant should be installed by an expert. He must

understand the fixtures, the size of the pipes, and the running of the boiler to secure the required degree of heat in a given type of building. The construction of the building and the amount of glass or muslin in front will influence the amount of heat required. In a brooder house one hundred feet long the best plan is to run two coils of two-inch pipe one on the back wall and one on the front, each coil containing two flow pipes and one return, in addition to the hover heat. In most conditions this should maintain a steady temperature of from 60° to 75° in all kinds of weather. In a brooder house in which the hovers are heated from a central heating plant, so much wall pipe may not be necessary, since considerable heat will be given off by the hover pipes themselves.

Before starting up the fire at the beginning of the brooding season, one should make sure that the system is full of water; if so, there will be water in the bottom of the glass in the expansion tank. If the air valves are not automatic, all of them should be left open when water is flowing into the tank, so that the air may escape from the pipes and permit them to fill with water. Neglect of this precaution, and starting the fire with too little water in the system, may burst the boiler.

A good practice is to start the fire and get it well under way before putting any coal on it. The use of coal is recommended, since it burns longer, gives a more uniform heat, and does not require much attention. To make the fire burn briskly, the pipe damper should be open and the upper door closed. When the fire is well started and there is a good bed of coals, and the water has reached the desired temperature, check the fire by closing the pipe damper and the damper in the ash-pit door, and leave the upper door ajar-how much ajar can only be learned by practice. This depends on the type of boiler, the varying amounts of water in the system, and will also be influenced by weather, wind, and rain. Never let the water in a hot-water system reach a temperature of 212°, for steam will then be formed, the water in the system will be greatly reduced, and there is danger of its boiling away and leaving the boiler dry. When it approaches this degree of temperature, the water should immediately be cooled by banking the fire and cutting off all drafts. If steam should form in the coils, some of it must be allowed to escape by opening the air valves, then let fresh water into the system gradually. It is best to have automatic valves. All ashes should be removed from the ash pit daily, for if they are allowed to remain they will

burn out the grate bars, as well as stop the drafts. The glass gauge should be examined frequently to ascertain whether there is plenty of water in the system. A desirable feature is a float valve on the expansion tank which will permit the automatic inflow of water when needed.

A thermometer connected with the heater to register the temperature of the water is very desirable, but, if one of these instruments is installed, it should be of reliable make, as a good deal of dependence is put upon it. All pipes in the brooder house which are not actually needed for direct radiation of heat should be covered with asbestos to conserve the heat, and all pipes used directly for heating should receive a good coat of paint to prevent rust.

REVIEW.

1. Describe two distinct systems in artificial brooding.

2. What three factors will aid in determining which type to select?

3. Discuss types and possibilities of the long brooder-house system.

4. Describe three types of colony brooders.

5. Discuss the possibilities of the "gasoline brooder house."

6. What are the four requirements of a successful brooder?

7. How would you prepare a brooder for young chicks?

8. How can the chilling of the chicks in transferring them be prevented?

9. Discuss proper brooder temperatures for different times.

10. Enumerate twelve principles of baby-chick feeding.

11. Why is ash so important?

12. What is the reason for not feeding soon after hatching?

13. Outline a desirable method of feeding baby chicks for the first six weeks; give rations.

14. Give five common causes of death of young chicks.

15. Discuss prevention against the white diarrhoea disease.

16. What are the dangers at the time the heat is removed?

17. What points are of special importance in locating and installing a heating plant for a long brooder house?

References. The Principles of Brooding, by Rice and Rogers, Cornell Bulletin 277. A Successful Brooder House, by F. H. Stoneburn, Connecticut Bulletin 33. Raising Chickens, by James E. Rice, Cornell Reading Course Bulletin 19. Raising Chicks Artificially, by Horace Atwood, West Virginia Bulletin 98. Feeding Experiments with Chickens, by J. Williard Bolte, Rhode Island Bulletin 126. Seven Methods of Feeding Young Chickens, by Rice and Nixon, Cornell Bulletin 282. The Mortality of Incubator Chicks, by G. W. Fields, Rhode Island Bulletin 61. Hatching and Rearing Chickens, by W. R. Graham, Ontario Bulletin 163. Skim Milk for Growing Chicks, by Plum and Anderson, Indiana Bulletin 76. The Baby Chick, by T. E. Quisenberry, Missouri Poultry Station Bulletin 1. Working Plans of N. Y. State Brooder House, Cornell Circular 4.

CHAPTER XXII.

CARE OF THE GROWING STOCK.

THE direct object in the feeding and care of all chicks, from hatching time to maturity, is growth. Uniform development is necessary for the laying birds or breeders. When meat production is the object, a rapid gain in flesh is desired to bring about a maximum profit in the least time. The discussions in this chapter will deal with the growing chick from weaning time to maturity.

Weaning the Chicks.-The best time to wean the chicks, whether it be from the mother hen or the brooder, will depend on the breed, the season of the year, the location of the colony houses, and the degree of protection which can be afforded them.

Leghorns and other light, active breeds are very susceptible to sudden changes early in their development. This is due to the strain on the system by excessive feather growth. Greater care must be used when changing them. They crowd badly if the temperature is too low; a heavy mortality follows. In the cold weather of early spring the weaning period must be postponed until the chicks attain a greater age than would be required if they were hatched later in the spring and were transferred during warmer weather. It is very undesirable to wean the chicks during damp weather.

The colony houses should be located in protected spots, especially early in the season, and near to the poultryman's residence. For the first few weeks after weaning, the chicks require quite close watching, as they have to be protected from sudden showers and extreme changes in weather conditions. The coops often require special manipulation during cool spells in late spring. If it is possible to arrange a portable hover in the centre of the colony house the chicks can be weaned much earlier. Such a hover may be made two feet square with felt or canvas curtains tacked to the edges of the board. Suspend this from the roof with cord and pulley, leaving it at first about ten inches from the floor. As the chicks develop and become accustomed to the changed conditions, the hover can be gradually raised, depending upon weather conditions, until they finally require it no longer.

It can then be stored away for use another year. This practice is very satisfactory with early-hatched Leghorn chicks..

Factors Affecting Growth.-There are many factors affecting the growth, development, and maturity of chickens. All of these logically fall under the one head, Environmental Conditions.

Environment Constantly Effective.-Environment, which is a word used to mean all of the conditions surrounding the individual, is a factor which is constantly acting for the good or for bad. As the surroundings tend toward bringing about the desired results in environmental conditions, rapid growth is attained from the very beginning. The growth which a chick makes is determined, in part, by the vigor and vitality of the parent stock, and the condition of the parent stock, also, in turn, is largely influenced by the surroundings to which they were subjected. Again, the vigor of

FIG. 170.-Growing poultry on free range is the most satisfactory method. Gasoline-heated brooders are used on this farm. (Photo by Cornell University.)

the germ in the fertile egg is influenced by the conditions under which the eggs were kept previous to hatching, and the development of the embryo is entirely determined by the surroundings to which the egg is subjected during the hatching process, such, for example, as variations in temperature, the degree of moisture, the amount of turning and cooling, and the general care of the incubator. At hatching time, differences in size and weight of chicks are in direct proportion to the humidity in the incubator, which directly affects the evaporation.

During the brooding period, the factors of environment are also of paramount consideration, feed and temperature being the controlling ones. It should be the aim of every poultry keeper to constantly study his birds, and, by careful selection and elimination, keep fewer but better birds. This is especially important.