The disease is usually controlled by the natural immunity. To develop this immunity exposure to low levels of the parasite which causes the disease. In order to ensure that the exposure does not allow rapid multiplicathe immune system, which may overwhelm the immune system, it is usual to add anti coccidia medications to the chick and grower foods.
However, dilution of the medication due to additional food sources, reduced immune capacity of the chicks, or excessive challenge due to poor management, additional treatments with coccidiostats may be necessary. It is vital to follow the instructions for dosage carefully, as inaccurate treatment can result in the birds developing immunity incorrectly.
The first signs of coccidiosis are usually soft to runny droppings. The droppings may be streaked with blood or black, and by that stage the chicks are usually ruffled and stand around with their eyes closed. Treatment is required quickly to save the chicks.
A common time of appearance of this disease is at about 8 weeks. This is usually about 2 weeks after the change of diet from chick starter to grower which has a different mediction level. At this time many people start to add extra grain and put the birds out on grass which further dilutes the medication level in the total feed, and allows the coccidiosis to develop before the proper immunity has developed.
Coccidiosis in adult chickens has 2 causes.
1/ The birds are reared in cages with no contact with their droppings so no way to contact with coccidiosis eggs to allow the infection which triggers their immune systems. If the adults are now moved to floor systems, they will contact lots of coxy eggs and have no ability to fight it off. Its like adolescent diseases in unvaccinated adult humans, they are far more serious.
2/ If the immune system is under attack from other diseases, coxy can become rampant, because the immune system no longer controls the disease. For this reason, many birds affected by other serious diseases can be mis-diagnosed as coxy but in fact is a secondary infection.
In the past Sulfa drugs have been the staple control method. However they are now all script only and can only be obtained from a veterinarian.