What are the dangers of backyard chickens?
Zoonotic diseases that backyard poultry may spread to humans include salmonel- losis, campylobacteriosis, and avian influenza viruses. Since the 1990s, numerous widespread outbreaks of human Salmonellaspp infections linked to contact with backyard chickens have been documented in the United States.
These lice, mites, ticks, and fleas will never jump from chickens to humans or to other animals; they are bird-specific. Another issue: Unlike deer ticks or dog ticks, these parasites don't actually feed on blood, instead chowing down on dead skin cells, feathers, and scales.
Infection may occur when you're handling live poultry, too, when you are cleaning out your coop area," said Davison, who gets calls everyday from backyard bird owners. Chicks and ducks may appear clean to the human eye, but they can still carry salmonella.
Backyard poultry, such as chickens and ducks, can carry Salmonella germs even if they look healthy and clean. These germs can easily spread to anything in the areas where the poultry live and roam.
It is common for chickens, ducks, and other poultry to carry Salmonella and Campylobacter. These are bacteria that can live naturally in the intestines of poultry and many other animals and can be passed in their droppings or feces. Even organically fed poultry can become infected with Salmonella and Campylobacter.
Chickens and other live poultry can carry Salmonella bacteria. These germs can spread from the birds to their eggs. If you eat raw or undercooked eggs, you can get sick. Always handle and cook eggs properly to prevent illness.
Transmission. Infections are often associated with international travel, undercooked poultry, unpasteurized milk, untreated water, and contact with farm animals. Eating undercooked chicken or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this infection.
Roundworms, also called ascarids, are the most common intestinal parasite found in poultry. These worms are species-specific, so there is little chance of cross infection among poultry species or from poultry to pets or humans.
Roundworms cannot be transmitted from chickens to humans.
Researchers swabbed the bottoms of 457 birds living on 50 backyard chicken farms in Finland and also tested boot socks from their human owners. They often found the bacteria Campylobacter jejuni and Listeria monocytogenes, both of which can transmit bothersome as well as potentially more serious infections to humans.
Is it good to have chickens in your backyard?
As the Gidneys have learned, keeping a small flock of chickens in your backyard has many benefits, from supplying you with fresh, healthy eggs from well-cared-for animals, to giving you great fertilizer for gardening, to providing lively pets—as well as being part of the drive to local, sustainable food systems.
Toxins: Endotoxins, which come from the cell walls of certain bacteria, are a component of poultry dust. Exposure to endotoxin causes acute respiratory symptoms, including a cough, shortness of breath and lung function impairment. Poultry workers with existing lung problems are even more susceptible.

A chicken bite is really harmless, considering the chicken is free from infection, bird flu or any poultry diseases. But even if it does posses any of the above mentioned health problems, it wouldn't kill you.
References
- https://www.quora.com/I-was-bitten-by-a-chicken-what-should-I-do
- https://the-chicken-chick.com/control-treatment-of-worms-in-chickens/
- https://edis.ifas.ufl.edu/publication/AA078
- https://www.health.state.mn.us/diseases/animal/backyard.html
- https://www.agweek.com/business/backyard-farmers-beware-your-chickens-can-make-you-sick
- https://modernfarmer.com/2016/01/backyard-chickens-parasites/
- https://www.greenamerica.org/green-living/many-benefits-backyard-chickens
- https://www.cdc.gov/foodsafety/communication/salmonella-and-eggs.html
- https://www.health.state.mn.us/diseases/campylobacteriosis/basics.html
- https://www.cbsnews.com/news/backyard-chicken-poultry-flocks-human-health-risk-cdc-warns/
- https://wsava.org/wp-content/uploads/2020/01/Clinician-s-Brief-March-2018-TP-Backyard-Chickens.pdf
- https://www.cdc.gov/salmonella/backyardpoultry-06-22/index.html
- https://commercialairfiltration.co.uk/blogs/news/poultry-dust-as-a-respiratory-hazard