Storey's Guide to Raising Chickens (42 page)

Nine different forms of cocci are caused by nine separate species of protozoa, each invading a different part of the chicken’s intestine. A chicken may be infected by more than one species at a time. Birds become immune in two ways: through gradual exposure or by surviving the illness. But they become immune only to the species occurring in their environment. Healthy chickens brought together from different sources may not all be immune to the same forms and may therefore transmit the disease to one another — with devastating consequences for the flock.

In young chickens the main signs of coccidiosis are slow growth and loose, watery, or off-color droppings. If blood appears in the droppings, the illness is serious — birds may survive but are unlikely to thrive. The disease may develop gradually, or bloody diarrhea and death may come on fast. In mature birds the chief sign is a decrease in laying. Infected older birds that appear healthy shed billions of eggs that readily infect younger birds.

If you suspect coccidiosis, take a sample of fresh droppings to your veterinarian and ask for a fecal test to find out what kind of coccidia are involved and
which medication to use. Not all anticoccidial medications work against all types of coccidia, and using the wrong drugs can do more harm than good.

Chicks reared early in the year while the weather is cool are in the best position to develop gradual immunity as the weather warms. If you raise chicks late in the season or in a year-round warm climate where coccidiosis is difficult to control, you may need to use a
coccidiostat
to prevent the condition, either by feeding a medicated starter ration or by lacing the drinking water with the coccidiostat. But medicate water with caution; chicks drink more in warm weather and can ingest a toxic dose.

SIGNS OF COMMON EXTERNAL PARASITES

Several species of mite survive by consuming the skin, feathers, or blood of a chicken. Mites cause irritation, feather damage, increased appetite, low egg production, reduced fertility, retarded growth, and sometimes death.

Red mites
, also known as chicken mites, are active in warm climates during summer and are especially attracted to broody hens. They invade chickens primarily at night, when they appear as tiny red or black specks on a bird’s body. After feeding they crawl along roosts to find a place to hide during the day. Adult mites can live for many months in unoccupied nests or housing. Control red mites by thoroughly cleaning the coop and dusting every crack and crevice with an insecticide approved for poultry.

Northern fowl mites
are active in cool climates during winter, causing scabby skin and darkened feathers around the vent. You’ll know you have this mite if you see tiny specks crawling on eggs in nests or on birds during the day. They may be repelled from nests by using cedar chips as nesting material, especially
for vulnerable setting hens. Since these mites increase rapidly, if you spot them, act fast by dusting birds and nests with an approved insecticide. Northern fowl mites cannot live long in an unoccupied chicken house, which will be free of them after about 3 weeks.

Northern fowl mites feed 24/7, leaving blackish debris and scabby skin around the vent.

Scaly leg mites
burrow under the scales of a chicken’s legs, making the scales stick out and causing the miserable bird to walk around stiff legged. Since leg mites travel slowly from one bird to another, they may be controlled easily by brushing perches monthly with a mixture of one part kerosene to two parts linseed oil (not motor oil) and at the same time coating each chicken’s legs with petroleum jelly (Vaseline).

Older birds are more likely to be infected than younger birds and are difficult to treat because the mites burrow deeply. Soak the bird’s legs in warm soapy water, and gently scrape or rub off the softened dead scales, then smother the mites by coating the legs with petroleum jelly daily for 2 weeks or until the mites are gone.

A chicken with a properly shaped beak can minimize lice on its body by grooming; a chicken that has been debeaked or has an overgrown beak is more likely to have lice because it cannot groom properly. Lice chew on a chicken, causing the bird to break off or pull out its feathers trying to stop the irritation. The resulting damage makes the plumage look dull or rough. Louse-infested chickens don’t lay well and have reduced fertility.

Lice spread through contact with an infested bird or its feathers and live their entire lives on a bird’s body. You can easily see the straw-colored pests scurrying around on a chicken’s skin, the scabby dirty areas they create around the vent and tail, and louse eggs (called nits) clumped in masses around the feather shafts.

If you spot signs of lice on one of your chickens, chances are they all have lice. An effective way to reduce the louse population is to diligently rake up and remove nit-laden feathers from the house and yard. Treatment involves applying a delousing product approved for poultry to the shelter walls, roosts, nest boxes, floors, and chickens. This treatment won’t kill nits, so it must be repeated two more times at 7-day intervals to zap lice that hatch between times.

Flies that bother chickens fall into two categories: biting flies and filth flies. Although filth flies don’t actually attack chickens the way that biting flies do, both spread disease.

Biting flies
are found primarily around bodies of water. The main ones that bother chickens are blackflies (also known as buffalo gnats or turkey gnats) and biting gnats (also known as midges, no-see-ums, punkies, and sand flies), the bites of which cause irritation. These flies are difficult to control, so your best bet is to keep chickens away from streams and stagnant water.

Filth flies,
including the common housefly, don’t bite, but they do transmit tapeworms (when eaten by a chicken) and spread diseases on their feet. Flies breed in damp litter and manure, so control involves keeping litter dry — fix leaky waterers and roofs, regrade to prevent runoff seepage around the foundation, and improve ventilation. Chickens help control flies be eating the flies and their larvae. If flies get out of control, avoid using insecticides, or you will end up with a resistant fly population. Instead, set out fly traps or a good-quality flypaper such as Sticky Roll, or introduce natural fly predators. Properly managed litter and manure accumulated over the summer will develop a natural population of fly predators.

Most backyard flocks kept for family meat and eggs, or just for fun, rarely experience serious illnesses. Your flock may not be so lucky if other flocks are housed nearby, if you habitually buy or trade chickens, if you regularly show your chickens, or if you run a small-scale commercial operation requiring a regular turnover in your poultry population. If any of these situations pertain to you, you’d be wise to get a comprehensive health-care guide such as
The Chicken Health Handbook,
which covers the large number of diseases — some mild, some devastating — to which chickens are susceptible.

As a chicken ages, its state of health changes in two opposing ways:

It develops resistance to some diseases in its environment.