The answer to this generalized question could very well form a thesis for a university graduate.
I will provide you with a good link for you to do your own research into this massive subject.
No, but chickens have their own raft of diseases.
Yes, turkeys can and will often catch diseases from chickens. This is why it is advised to keep turkeys and chickens separate, this way the turkeys cannot catch the disease from the chickens.
The disceses are from humans having sex with them
yes
Two common gastrointestinal diseases are endemic Newcastle's Disease and low-path avian influenza; both of these diseases circulate in the wild bird population, so any chickens exposed to wild birds are susceptible. There are other diseases, but the frequency of them varies depending upon where you are located and how much exposure your chickens have to the outdoors. Common parasites include mites, ticks and fleas; most chickens control these through dust baths and frequent grooming of their feathers, so unless it gets severe you don't need to worry about treating the chickens for these.
It depends on what your definition of "better" is. Chickens are a food source. They provide meat and eggs. Squirrels are not a sustainable food source. Chickens carry diseases such as aviation flu. Squirrels carry diseases such as hemorrhagic fever. Chickens are not cute (to most). Squirrels are cute (to many). Chickens can be domesticated and farmed. Squirrels cannot be domesticated because they are classed as a pest.
Fayoumi. They can fight off any bacterial infection.Count Olaf
it can transfer diseases to human like bird flue ... !
Farmer Jones kept his chickens away from other animals to prevent the spread of diseases. Chickens can carry various pathogens that may not affect them but could be harmful to other livestock. By maintaining separation, Farmer Jones reduces the risk of cross-species transmission of diseases, ultimately protecting the health of his entire livestock.
Breeding inbred chickens for the poultry industry can lead to negative consequences such as reduced genetic diversity, increased susceptibility to diseases, and lower overall productivity and quality of the chickens.
A. S. Dhillon has written: 'Vaccination recommendations for chickens' -- subject(s): Chickens, Diseases, Handbooks, manuals, Handbooks, manuals, etc, Prevention, Vaccination
Signs of inbreeding in chickens may include reduced fertility, increased susceptibility to diseases, lower growth rates, and physical deformities such as crooked beaks or legs.