Mycoplasma galisepticum

salmonella, fowl cholera (pasteurella), mycoplasma, E. coli

well, i think it depends on the geographical location when you mention thinks like which one is the most important. for example, a bacterial disease can be very important and could have high mortality in west Africa than it would in Asia.

Unless you general mean a bacterial disease with significant threat to global poultry production

cheers

Mycoplasma, ornithobacter, sakmonella

Mycoplasma