Chapter 24
DISEASES
For the study of the classification and description of the numerous ailments by which individual fowls pass to their untimely end, I recommend any of the numerous books written upon the subject. Some of these works are more accurate than others, but that I consider immaterial. The study of these diseases is good for the poultryman, it gives his mind exercise. When a boy in high school I studied Latin for the same purpose.
Don't Doctor Chickens.
For the cure of all poultry diseases when they have passed a point when the fowl does not eat or for other reasons recovery is improbable, I recommend a blow on the head--the hatchet spills the blood which is unwise.
The usual formula of "burn or bury deeply" is somewhat troublesome, unless you have a furnace running. A covered pit is more convenient if far enough removed from the house that the odor is not prohibitive. A post with a tally card may be planted near by. This part of the poultry farm may be marked "Exhibit A," and shown first to the visitor during the busy season. If he is one of those prospective pleasure and profit poultrymen who propose to disregard all facts of biology and economics of production, you may save yourself the trouble of showing him the rest of the plant. Unfortunately, this scheme is not open to the poultryman who has breeding stock for sale.
I have frequently had the question put to me in the smoker of a Pullman car, "Do not epidemic diseases make the poultry business precarious?" Such questions came from farm-raised men, but not from poultry farmers. Poultrymen should figure a certain loss of birds just as insurance companies figure on the human death rate, but to all practical intents and purposes the epidemic disease has been banished from the poultry farms and seldom if ever enters the records in answer to the question, "Why do poultry farms fail?"
Some of my readers may take exception to me either in regard to roup or white diarrhoea. Roup is a disease of the wrong system and careless management. White diarrhoea, so-called, is a matter of wrong incubation.
The high mortality of young chicks, though not an epidemic disease, shares with excessive cost of production, very much of the responsibility for poultry farm failures. At the present writing the poultry editors of the country are having much discussion over the conclusion of Dr. Morse of the Bureau of Animal Industry to the effect that white diarrhoea is caused by an intestinal parasite similar to the germ that causes human dysentery. Dr. Morse's opportunities for investigation have been somewhat limited and as the intestines of any animal are always swarming with various organisms, it will take very conclusive evidence to prove that the doctor is right. Practically the naming of the germs that attend the funeral is not particularly important for the reason that it has been thoroughly demonstrated that with good parentage, good incubation and good brooder conditions, white diarrhoea is unknown.
The Causes of Poultry Diseases.
Poultry ailments are assignable to one of the three following causes, or a combination of these: First, hereditary or inborn weakness; second, unfavorable conditions of food, surroundings, etc.; third, bacteria or animal parasites.
A great many chickens die while yet within the shell, or during the growing process, there being no assignable reason save that of inherited weakness. To this class of troubles the only remedy is to breed from better stock. It is as much the trait of some birds to produce infertile eggs or chicks of low vitality as it is for others to produce vigorous offspring.
The second class of ailments needs no discussion save that accorded it under the general discussions of the method of conducting the business.
The third class of ailments includes the contagious diseases. It is now believed that most common diseases are caused by microscopic germs known as bacteria. These germs in some manner gain entrance to the body of an animal, and, growing within the tissues, give off poisonous substances known as toxins, which produce the symptoms of the disease. The ability to withstand disease germs varies with the particular animal and the kind of disease. As a general rule it may be stated that disease germs cannot live in the body of a perfectly vigorous and healthy animal. It is only when the vitality is at a low ebb, owing to unfavorable conditions or inherited weakness, that disease germs enter the body and produce disease.
The bacteria which cause disease, like other living organisms, may be killed by poisoning. Such poisons are known as disinfectants. If it were possible to kill the bacteria within the animal, the curing of disease would be a simple matter, but unfortunately the common chemical poisons that kill germs kill the animal also. The only thing that can be relied upon to kill disease germs within the animal, is a counter-poison developed by the animal itself and known as anti-toxin. Such anti-toxins can be produced artificially and are used to combat certain diseases, as diphtheria and small-pox in human beings and blackleg in cattle. Such methods of combating poultry diseases have not been developed, and due to the small value of an individual fowl would probably not be commercially useful even if successful from a scientific standpoint. The only available method of fighting contagious diseases of poultry is to destroy the disease germs before they enter the fowls and to remove the causes which make the fowl susceptible to the disease.
Contagious diseases of poultry may be grouped into two general classes: First, those highly contagious; second, those contracted only by fowls that are in a weakened condition. To the first class belong the severe epidemics, of which chicken-cholera is the most destructive.
Chicken-Cholera.
The European fowl-cholera has only been rarely identified in this country. Other diseases similar in symptoms and effect are confused with this. As the treatment should be similar the identification of the diseases is not essential.
Yellow or greenish-colored droppings, listless attitude, refusal of food and great thirst are the more readily observed symptoms. The disease runs a rapid course, death resulting in about three days. The death rate is very high. The disease is spread by droppings and dead birds, and through feed and water. To stamp out the disease kill or burn or bury all sick chickens, and disinfect the premises frequently and thoroughly. A spray made of one-half gallon carbolic acid, one-half gallon of phenol and twenty gallons of water may be used. Corrosive sublimate, 1 part in 5000 parts of water, should be used as drinking water. This is not to cure sick birds, but to prevent the disease from spreading by means of the drinking vessels. Food should be given in troughs arranged so that the chickens cannot infect the food with the feet. All this work must be done thoroughly, and even then considerable loss can be expected before the disease is stamped out. If cholera has a good start in a flock of chickens it will often be better to dispose of the entire flock than to combat the disease. Fortunately cholera epidemics are rare and in many localities have never been known.
Roup.
This disease is a representative of that class of diseases which, while being caused by bacteria, can be considered more of a disease of conditions than of contagion. Roup may be caused by a number of different bacteria which are commonly found in the air and soil. When chickens catch cold these germs find lodgment in the nasal passages and roup ensues. The first symptoms of roup are those of an ordinary cold, but as the disease progresses a cheesy secretion appears in the head and throat. A wheezing or rattling sound is often produced by the breathing. The face and eyes swell, and in severe cases the chicken becomes blind. The most certain way of identifying roup is a characteristic sickening odor. The disease may last a week or a year. Birds occasionally recover, but are generally useless after having had roup.
Sick birds should be removed and destroyed, but the time usually spent in doctoring sick birds and disinfecting houses can in this case be better employed in finding and remedying the cause of the disease. Such causes may be looked for as dampness, exposure to cold winds, or to a sudden change in temperature as is experienced by chickens roosting in a tight house. Fall and winter are the seasons of roup, while it is poorly housed and poorly fed flocks that most commonly suffer from this disease. Flocks that have become thoroughly roupy should be disposed of and more vigorous birds secured. The open front house has proved to be the most practical scheme for the reduction of this disease.
Chicken-Pox, Gapes, Limber Neck.
Chicken-pox or sore-head is a disease peculiar to the South. It attacks growing chickens late in the summer. Southern poultrymen who give reasonable attention to their stock, find that, while this disease is a source of some annoyance, the losses are not severe and that it may be readily controlled. In the first place, the animal epidemic of pox can be practically avoided by bringing the chicks out early in the season. If the disease does develop in the flock, the birds are taken from the coops at night and their heads dipped in a proper strength of one of the coal tar disinfectants. Such treatment once a week has generally been effective. This disease is an exception to the general rule that disinfectants which kill germs also kill the chicken. The explanation is that chicken-pox is an external disease.
Gapes is given in every poultry book as one of the prominent poultry diseases, but are not common in the Northern and Western States. Gapes are caused by a parasitic worm in the windpipe. Growing chicks are affected. The remedy is to move the chicks to fresh ground and cultivate the old.
Limber neck is not a disease, but is the result of the fowl's eating maggots from dead carcasses. It can be prevented by not allowing dead carcasses to remain where the chickens will find them. No practical cure is known.
Lice and Mites.
The parasites referred to as chicken-lice include many different species, but in habit they may be classed as body-lice and roost-mites. The first, or true bird-lice, live on the body of the chicken and eat the feathers and skin. The roost-mite is similar to a spider and differs in habits from the body-louse in that it sucks the blood of the chicken and does not remain on the body of the fowl except at night.
Body-lice are to be found upon almost all chickens, as well as on many other kinds of birds. Their presence in small numbers on matured fowls is not a serious matter. When body-lice are abundant on sitting hens they go from the hen to the newly hatched chickens, and may cause the death of the chicks. The successful methods of destroying body-lice are three in number: First, dust or earth wallows in which the active hens will get rid of lice. Such dust baths should be especially provided for yarded chickens and during the winter. Dry earth can be stored for this purpose. Sitting hens should have access to dust baths. Second: The second method by which body-lice may be destroyed is the use of insect powder. The pyrethrum powder is considered the best for this purpose, but is expensive and difficult to procure in the pure state. Tobacco dust is also used. Insect powder is applied by holding the hen by the feet and working the dust thoroughly into the feathers, especially the fluff. The use of insect powder should be confined to sitting hens and fancy stock, as the cost and labor of applying is too great for use upon the common chicken. The third method is suitable for young chickens, and consists of applying some oil and grease on the head and under the wings. Do not grease the chick all over. With vigorous chickens and correct management the natural dust bath is all that is needed to combat the lice.
The roost-mite is probably the cause of more loss to farm poultry raisers than any other pest or disease. The great difficulty in destroying mites on many farms is that chickens are allowed to roost in too many places. If the chicken-house proper is the only building infected with mites the difficulty of destroying them is not great. Plainness in the interior furnishings of the chicken-house is also a great advantage when it comes to fighting mites. The mites in the daytime are to be found lodged in the cracks near the roosting-place of the chickens.
Mites can be killed with various liquids, the best in point of cheapness is boiling water. Give the chicken-house a thorough cleaning and scald by throwing dippers of hot water in all places where the mites can find lodgment. Hot water destroys the eggs as well as the mites. Whitewash is a good remedy, as it buries both mites and eggs beneath a coating of lime from which they cannot emerge. Pure kerosene or a solution of carbolic acid in kerosene, at the rate of a pint of acid to a gallon of oil, is an effective lice-paint. Another substance much used for destroying insects or similar pests is carbon bisulphide. This is a liquid which evaporates readily, the vapor destroying the insects or mites. Carbon bisulphide or other fumigating agents are not effective in the average chicken-house because the house cannot be tightly closed. The liquid lice-killers on the market are very effective. They are usually composed of the remedies just mentioned, or of something of similar properties.