If you have backyard chickens, there are measures you should take to:
Salmonella bacteria are very common in chickens. Many have the bacteria in their droppings or even on their bodies. Salmonella can cause:
If you are elderly, have an infant, or have a weakened immune system you are more likely to get very sick or be hospitalized from salmonella.
Lead can contaminate eggs, leading to lead poisoning in those who eat the eggs. The highest levels of lead are usually found in the yolk and shell. Eating soil contaminated with lead is the most common way chickens are exposed to lead. Things that can contaminate the soil include:
State Lab of Hygiene can test soil and egg yolks for lead. Call (800) 442-4618.
Rats are attracted to chicken coops as a source of food. If they have access to your coop, infestations can occur.
Eliminate their food source:
How to Get Rid of Rats in the Chicken Coop: The Definitive Guide, Backyard Chicken Project