Chicken to Human Diseases?

All animals, from crustaceans to humans, are hosts, both inside and out, to multitudes of bacteria and viruses. Kept in check they actually keep us healthy. Some bacteria even do essential body processes. For example, goats need bacteria in their guts to digest grass. New research shows that even the so-called “bad bacteria” have important roles to play. It’s when things get out of balance that health issues occur.

The chickens in our backyards carry around their share of germs and it’s prudent to worry about whether we can get sick from them. The quick answer is that there are very few diseases that humans and birds share. Our biologies are just too different. That said, there are a small number of pathogens to know about, all of which can be neutralized by hand washing and good animal husbandry. The truly scary diseases are not coming from the backyard flock, they’re coming from animal factories (let’s not call them “farms.”)  I’m not going to go into a diatribe here about how crowded factory production facilities that rely on antibiotics to keep their animals alive are creating “superbugs” that are resistant to drugs, I’m sure you’ve read this on-going story in the press. Instead, let’s go over what you need to know about the hens in your backyard.

The biggest fear that many have is of Bird Flu. My readers in North America don’t have to worry about this.  We’ve never had a case of Avian Influenza here. For those in other parts of the world, it appears as if actually coming down with the disease requires close contact with the dead bird (such as when people stripped the feathers off of deceased swans.) In Asia, avian influenza shows up in people who are living in close contact with large numbers of birds, usually waterfowl, not chickens.

Another disease that you might have heard is zoonotic (transmissible from animal to human) is Newcastle Disease. Rest assured that it isn’t of great concern for backyard chicken keepers. In chickens it causes respiratory ailments. Transmitted to humans it triggers mild conjunctivitis, but even this is usually only seen in people who administer the Newcastle vaccine to poultry, or are lab workers who do necropsies. Two other zoonotic diseases are erysipelas and chlamydiosis, which are mostly hosted by turkeys, and only affect humans who work in slaughterhouses, and farmers of large flocks. Avian tuberculosis is another one that is quite rare (it’s more prevalent with parrot fanciers) but possible to contract.

Internal and external parasites are species specific and as nasty as lice and worms look, they’re not going to infect your gut if you somehow ingest them. The three bacterial pathogens that are of concern are Salmonella spp., Complyobacter spp., and E. Coli. Generally, people get sickened by these bugs after eating improperly cooked and handled meat and eggs that have been contaminated with the germs, not by handling live and healthy chickens. Yes, poultry harbor these pathogens in their systems, but simply washing your hands after holding your hens is generally enough to prevent disease transmission. One exception that occurred recently involved chicks from large hatcheries. Children who kissed the chicks came down with salmonella.

Other issues that might come up, but that aren’t transmissible diseases, are allergies, and respiratory irritations due to mold and dust. Some people are allergic to the dander that chickens are constantly making as they grow and shed feathers. Chickens also create a fine dust out of bedding material and manure that they shred to bits as they scratch the ground. Sometimes bedding or feed will become moldy, especially if there’s been a long rainy period. Any respiratory and allergic reactions to these irritants can be minimized when one practices good manure management, and has a well-ventilated and dry coop.

An article published by the Penn State College of Agricultural Sciences put it well. People should not fear close association with poultry as a significant human health risk. So, enjoy your hens. Handle them and spend time with them. Just don’t kiss them.


  1. Sadly, I lost my favorite vet Dr. Susie Peterson to Avian TB. She contracted it while in vet school from a parrot. :( I remember a out break of Newcastle’s when I was a kid in NJ & PA but have not heard of one since.

  2. I second Maryanne’s comment.

    The other day in the news they had a story about how kids playing in the dirt and even eating a little of it was actually good for their immune systems. I wanted to stand and scream FINALLY!!!
    My grandson will be a year old in August and I couldn’t believe all the “precautions” that were taken, many suggested by his doctor. Sanitize wipe this, sanitize gel that, hypoallegenic this blah, blah, blah. I told my son I’m shocked the human race has survived this long.

    • Studies are also showing that children exposed to pets have fewer allergies. I think you have a lot of grandkid watching to do, Ken! :)

  3. It’s undeniably hard not to squish my cute little hens. I love them so. My son said to me the other day as we were headed out the door to check on them……..”Mom, don’t forget to put on your chicken shoes”

  4. Terry, what is your epsom salt to water ratio when orally dosing the hens, what is the most effective thing for getting rid of or reducing mites, and when bathing hens in this hot weather is it necessary to blow dry them?

    • 1 teaspoon epsom salt per ounce of water.
      Mite are tough to kill off. They live during the day in the wood crevasses, so bathing won’t kill them. I suggest spraying on a miticide while the hens are roosting, and during a through barn clean (painting the coop can help reduce their hiding places.)
      You can towel dry your hen, but if she’s wet all over, let her dry in a crate before putting her back with the flock.