Canadian Poultry Magazine


By Jacob Biely   

Features 100th anniversary Technology Poultry Research Research

October 1934

Coccidiosis as a severe disease is largely due to the development of specialized poultry raising.  Responsible for it are: (1) the large rearing unit; (2) limited range; (3) continuously used range; (4) proximity of poultry farms and (5) increased trafficking in fowls.

His statement does not signify that specialized poultry farming is doomed to failure because of coccidiosis.  It does, however, emphasize the necessity of recognizing the importance of this problem and becoming adequately informed.

The Cause – A small parasite distinguishable only under the microscope has been established beyond question as the cause of coccidiosis.  Various forms of mismanagement or feeding of the flock, resulting in lowered vigor, are often regarded as primary factors in the production of the disease, but erroneously so.  There is so much experimental and field evidence to disprove these assumptions, that they would not be worthy of mention here if it were not for the fact that many interested in poultry still cling to such misconception.  It should be obvious that these muddle the situation and stand in the way of successful control.


Kinds of Coccidiosis – At least six kinds of coccidian are found in chickens, five of which affect particularly the small intestine and one the ceca and rectum. One is capable of causing severe bleeding from the ceca and the rectum, another from the small intestine.  The remaining four as a rule cause slight or no bleeding, but do cause excessive amounts of mucous or slime in the small intestine and droppings.

The Nature of the Parasite and the Disease – When the fowl eats contaminated material the parasite gains entrance and passes into the intestines.  In the meantime the parasite undergoes various changes and finally emerges in an egg form, or what is known as an oocyst.  It then passes out in the droppings.  This stage is not capable of producing disease. The fresh droppings from an infected fowl will not produce coccidiosis.

After being passed in the droppings, the oocyst undergoes a change, it proper conditions of moisture, air and temperature are provided.  At this stage the parasite is capable of producing disease.

About four to six days, depending upon the kind of coccidiosis present, are necessary for the parasite to attain much development after being consumed.  During the succeeding few days, heavily infected fowls discharge millions of oocysts in the droppings and thus expose others to infection.

Severity of the Disease Dependent Upon Number of Parasites Consumed – The number of oocysts consumed determines the severity of the disease.  Fowls infected with small numbers appear perfectly healthy.  Young fowls infected with a large number for the first infection regularly die with the disease in the case of the bloody types.  Older fowls may show considerable cecal hemorrhage or bleeding and recover, but are not so likely to recover with small-intestine infection accompanied by bleeding.  The fact that severity of the disease is determined by the number of coccidia is of considerable importance, as it means that reducing the number serves as a control measure.  This is accomplished by sanitation.  Since the oocysts pass out in greatest numbers during the first week after symptoms develop, the value of frequent cleaning during that period is obvious.

Method of Distribution – The parasite may be carried mechanically on the shoes, by flies, birds, used brooder equipment, which has not been thoroughly cleaned, streams, or irrigation ditches.  Used unsterilized feed sacks may also act as a carrier, but are probably not a frequent source. In other instance the purchase of infected fowls is a source of infection.  It is highly important to remember that mature fowls provide a very likely source of infection for your stock on the same farm.  Droppings from the mature fowls, adhering to the attendant’s shoes, perhaps afford the most common means of carrying the parasite to the brooder stock.

Seasonal Conditions exercise a distinct influence on the development of coccidiosis.  This is due to the fact that moisture and warmth provided during the spring and summer months permit of rapid and regular development of the oocyst to the stage, which is capable of producing the disease.  Therefore, it more frequently occurs in severe form at such times.  It is possible for severe coccidiosis to develop during the winter.  When this occurs the source of infective oocysts is likely to be soil or material contaminated during the warm season or contaminated material during the warm season or contaminated material kept warm by the brooder stove.

Symptoms and Diagnosis – The symptoms in many cases of coccidiosis may not differ from those of a number of other diseases. This is particularly true when moderate infection exists.  Where very mild infection occurs there may be no outward evidence. These cases can be diagnosed only with the aid of a microscope.  There are times, however, when the average poultry raiser could hardly be mistaken in making a diagnosis.

Severe sudden outbreaks of cecal and sometimes small intestine coccidiosis are accompanied by the passage of distinct amounts of pure blood in the droppings.  Young fowls affected with severe coccidiosis may die suddenly, without any symptoms having been noticed other than a pale comb, and a slight amount of blood on the vent fluff.  Fowls dying under such circumstances may be in perfect flesh and show no symptoms until a few hours before death.  They should be examined and the condition of the intestines noted.  Such fatal cases of coccidiosis will often show the ceca or blind intestines bulging with pure blood, or in other instances such material will occur in the small intestine usually some distance below the gizzard.  When the small intestine is so affected, it is common for it to be distinctly enlarged where the infection is most severe.

If the infection is moderately severe, the fowl will usually be droopy for several days up to a week or two, lose weight, and die during this period, or gradually show less symptoms and possible come back to normal weight. When many fowls in growing flocks appear droopy, and no other cause for disease can be determined, it is usually the safest plan to conclude that coccidiosis is the cause the apply sanitation accordingly.

Effect Upon Fowls of Laying Age – Fowls, which have not been infected during the rearing period, may be disastrously affected in the laying-house. Such flows consuming large doses of coccidia may show a slight to complete lack of egg production with six kinds of coccidiosis.

Coccidiosis and Paralysis – Paralysis is not infrequently stated to be brought on by coccidiosis.  Since coccidiosis is so widespread it is not at all surprising that the two are frequently found in the same fowl.  This does not signify that paralysis is due to coccidiosis.  Paralyzed fowls may show large numbers of coccidia or none at all.  This does not prove that coccidia are or are not the cause of paralysis.  Fowls, which are free from coccidiosis, may have been infected in the past and in fowls, which are infected the parasites, may have no relationship to the paralysis. Substantial evidence at hand contradicts the hypothesis that paralysis is due to coccidia.

Prevention – “Sanitation is the foundation of coccidiosis control…. The inauguration of sanitary measures on an economic basis cannot be expected totally to eliminate coccidium infection, but they should result in holding infection down to a low degree, and permit of successful rearing.”  These statements, made a number of years ago, are still consistent with the known facts. 

Rearing fowls absolutely free of coccidiosis is highly undesirable if they are later to be kept under average commercial flock conditions.  Such fowls would then be disastrously affected, so far as mortality and egg production are concerned, if they obtain large numbers of the parasite.  Management factors, which allow the fowls to consume small doses during the growing period, are more likely to prove satisfactory.  This by no means constitutes a recommendation for the use of methods generally recognized as insanitary.

Soil Conditions – Well-drained soil provides the most suitable land.  This type dries out more readily and therefore assists in preventing development of the oocyst.  Those, which do develop, are likely to die more quickly in dry soils than in damp soils.

The common practice of plowing the yard and growing a crop is to be recommended, but this cannot be relied upon to rid the soil of all coccidia.  Annual plowing and leaving the yards idle for three or four years will probably result in practically all of the oocysts being destroyed since they would, during such time, be subjected to drying, which is very destructive to them.  Where only one or two yards are provided, it is perhaps best not to plow at all, but to sweep the yards and haul the sweepings away.  Plowing or spading the yards during an outbreak only serves to encourage the disease.

Types of Brooding and Equipment – The colony brooder, which is moved to new land, offers one means of controlling coccidiosis. Until recent years it has been the most accepted method of brooding to control intestinal parasites.  This method has the disadvantage of high labor cost.

The permanently located brooder provides a particularly desirable type of brooding from the standpoint of convenience and labor.  It is frequently open to objection because of its tendency to aggravate the development of coccidiosis.

In order to overcome the objection to the permanently located brooder, because of its favoring intestinal parasitic diseases, an artificial yard is sometimes used.  This commonly consists of concrete or wire netting.  Such a yard preferably extends the length of the brooder.  It may be up to about 20 feet in width. The wire yard does not require frequent cleaning. While the concrete yard requires more frequent cleaning, it gives some opportunity for the fowls to acquire coccidial infection in mild form and to develop immunity.  Having such a yard permits of cleaning it as thoroughly as the house and with slight labor.  It is desirable to have the concrete yard sloped about eight to ten inches away from the brooder.  It may be covered with sand or not, as desired.

One should not conclude that the concrete yard itself eliminates the losses.  It merely provides suitable conditions for assisting in prevention and particularly for control when a severe outbreak occurs.  It also assists in controlling other intestinal parasite diseases, especially roundworms and some tapeworms.  As soon as brooding is completed, the fowls should be moved to range houses provided with wire floors high enough to prevent access to the droppings.

Drinking vessels placed on wire-covered or slatted frames will prevent access to moist places and will prevent the birds from consuming moist droppings.  Wire floors over the entire brooder floor are undesirable.  Coccidiosis may be entirely prevented by such equipment and if the fowls are placed on litter or soil later, serious coccidiosis may result.  If one must resort to the use of such equipment to control coccidiosis, it would perhaps be preferable to go out of the business.

Range Conditions – Flocks on range present a difficult situation when seriously affected with the disease.  Under such circumstances the houses should be moved farther apart to provide to flows with increase range.  This reduces the degrees of contamination in the soil and accordingly the possibility of severe infection.

Treatment is of secondary importance, and can be recommended only as a means of making the best of an already bad situation, not as a routine preventive.  Coccidiosis occurs in spite of any treatment, which has been reported.  Feeding a ration consisting of about 20 per cent powered skim milk or buttermilk assist s in controlling cecal coccidiosis accompanied by blood.  When this amount of dried mil is given, an ample supply of water must be provided, as considerably more is consumed than normally.  It is advisable also to provide more driking space. 

Control of Sudden, Severe Outbreak – When outbreaks of this nature occur involving bleeding from the ceca, the above mentioned milk feeding is advised to be continued for a week or ten days.  Milk feeding may have no value for the control of coccidiosis of the small intestine.  Its use offers definite objections from the standpoint of causing the droppings to become more liquid, thus favoring development of the oocysts in the litter.  The following, which is essentially the so-called “Wisconsin” ration, may be used as an all-mash ration for the control of cecal infection:

Ingredients                Parts by weight

Ground yellow corn                      80 

Wheat middlings                          20

Bone meal                                   5

Limestone grit                              5

Fine salt                                      1

Dried milk (skim or buttermilk)     30

Daily cleaning of the house is an advantage and the yard should be swept daily until marked improvement in the flock results.

If the weaker fowls are separated from the others, they do much better, the deaths are less, and the well fowls are less likely to become infected.

Moist places frequently occur where the fowls drink.  Special precautions are taken to eliminate these moist places during warm weather and near the brooder stove at all times.

Flocks showing a severe outbreak can sometimes be handled to advantage by taking the cockerels out and placing them in fattening crates with wire bottoms so that the droppings pass through and cannot be reached by the fowls. This management alone will prevent further losses other than those already severely infected.

Additional heat is necessary during acute outbreaks, particularly when feeding liberally of milk or milk products.  More careful observation is necessary to prevent losses due to huddling.

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