Should People with Weak Immune Systems Raise Chickens?
A healthy adult person has little to fear from keeping chickens, but those with impaired immune systems due to age, cancer, HIV infection, diabetes, or other medical conditions should resist the impulse to bring home cute, fluffy chicks from the feed store. Raising chickens may not be a wise pursuit for them.
Several chicken-borne diseases are unpleasant for healthy adults, but they can cause severe illness and death in people with weak immune systems. High-risk diseases for immunosuppressed people include
Campylobacteriosis. This is one of the most common bacterial infections of humans. It causes cramps, pain, fever, and severe diarrhea. Campylobacteriosis is often a foodborne illness, but contact with pets (especially puppies), poultry, and livestock can also cause it. Campylobacter is the most common cause of "traveler's diarrhea" and usually goes away on its own. In a person with a weakened immune system, the bacteria can cause serious complications.
Salmonellosis. A salmonella infection causes diarrhea, fever, vomiting, and abdominal cramps. The illness lasts up to seven days and most people recover without treatment. But some cases of the diarrhea can be so severe that a person becomes dangerously dehydrated and must be hospitalized. Humans can pick up salmonella from chickens by handling infected eggs. Undercooked meat, unwashed fruits and vegetables, and reptiles can also cause salmonella infection.
Avian tuberculosis. Most humans are highly resistant to this bacteria, but people who have AIDS, who are undergoing cancer treatment, or who have had an organ transplant are susceptible to it (and one strain of avian tuberculosis is resistant to antibiotics). Avian tuberculosis in humans causes localized wounds on the skin with swelling of lymph nodes on the same parts of the body.
Parrot fever. In humans, symptoms of parrot fever range from nothing to high fever, cough, and severe pneumonia. Rose-colored spots may appear on the skin, and in some cases a patient becomes unresponsive or comatose. As bad as it sounds, parrot fever has only a 1% fatality rate in humans. People can pick up parrot fever from chickens, pigeons, macaws, ducks, gulls, and many other bird species.
Histoplasmosis. Going by many names (Cave disease, Ohio valley disease, Darling's disease), histoplasmosis starts with a cough and flu-like symptoms but can advance to resemble tuberculosis. While it often affects the lungs, it can spread to other organs and be fatal if not treated. Contact with contaminated bird and bat droppings are the most common causes of bird-to-human infection.
To be fair, pet chickens aren't known to be the most common sources of infection for any of these diseases. (Dogs and cats can carry Campylobacter and Salmonella, too, and household birds are more likely than chickens to carry the bacteria that cause parrot fever.) But because the risk from chickens is small but real, the U.S. Centers for Disease Control and Prevention and many physicians discourage people with weak immune systems from keeping pet poultry. If you're concerned, talk with your doctor.

Raising Chickens Glossary
broiler; broiler bird
Any chicken of a breed known or developed for meat; usually with deeper, larger breasts, a larger frame, and fast growth.

Raising Chickens Glossary
brooder
An enclosed area for chicks in the first few weeks of life; provides warmth and safety in the absence of a mother hen.

Raising Chickens Glossary
chiggers
A common external parasite of chickens (and humans) that feed on blood while injecting an irritant into the skin.

Raising Chickens Glossary
Coccidia
An internal parasite of chickens that lines the digestive tract and may cause serious problems.

Raising Chickens Glossary
coccidiosis
An infection by Coccidia.

Raising Chickens Glossary
coccidiostats
A medicine that controls the disease coccidiosis; often added to commercial chicken feed.

Raising Chickens Glossary
cockerel
A young male chicken.

Raising Chickens Glossary
County Extension agent
A county employee, sometimes called an educator, who is associated with a land-grant university in the same state and whose job is to take research-based knowledge and bring it to the general public.

Raising Chickens Glossary
crumbles
Medium-sized pieces of feed, actually broken-up pellets.

Raising Chickens Glossary
egg binding
The condition that occurs when a hen has an egg that she can’t pass from the oviduct for some reason.

Raising Chickens Glossary
fowl tick
An external parasite of chickens, common in the U.S. South, that feed on the chicken’s blood but do not stay attached.

Raising Chickens Glossary
gapeworm
A common internal parasite of free-range or pastured chickens, usually found in the trachea; may cause serious breathing problems.

Raising Chickens Glossary
grit
1. Small rocks or gravel; aids digestion for chickens. 2. Chicken feed supplement, made of crushed limestone and granite, available for purchase in feed stores for chickens requiring extra grit.

Raising Chickens Glossary
hybrid
A cross between two chicken breeds, usually created to take advantage of specific qualities such as increased breast meat.

Raising Chickens Glossary
layer; laying hen
Any chicken of a breed known or developed for laying eggs; will not sit on their own eggs.

Raising Chickens Glossary
lice
A common external parasite of chickens that feeds on feathers or shedding skin cells.

Raising Chickens Glossary

Raising Chickens Glossary
mite
A common external parasite of chickens that burrows into the chicken’s skin and feeds on chicken blood.

Raising Chickens Glossary
oocysts
Immature Coccidia that are passed in fecal matter. Coccidia is an internal parasite of chickens that lines the digestive tract.

Raising Chickens Glossary
parasite
Things that feed on a chicken’s blood, other body secretions, or its feathers; may be internal or external.

Raising Chickens Glossary
pellets
Long, narrow, cylinder-shaped pieces of compressed feed.

Raising Chickens Glossary
pullet
A young female chicken who has not started laying eggs.

Raising Chickens Glossary
roost
1. (noun) Any above-floor structure provided for a bird to perch on. 2. (verb) The act of perching on such a structure.

Raising Chickens Glossary
roundworm
A common internal parasite of chickens, usually found in the intestines but occasionally in the oviduct or even an egg

Raising Chickens Glossary
shelter-and-run unit
A form of chicken housing that combines an indoor, protected area with an outside enclosure.

Raising Chickens Glossary

Raising Chickens Glossary
tapeworm
A common internal parasite of chickens, usually found in the intestines and usually considered harmless.

Raising Chickens Glossary
vent; vent area
The common opening for feces in chickens.

Raising Chickens Glossary
vet wrap
A bandage, often used with animals, that sticks to itself.

Raising Chickens Glossary
zoning variance
A formal agreement with the governing body of an area to allow one individual or entity to deviate from the restrictions of a zoning area.

Raising Chickens Glossary
zoning; zoning area
1. (noun) An area or district with specific restrictions or rules about the types of buildings and activities that can take place there. 2. (adjective) Of or about the restrictions required due to the zoning area.