The thing people who havent done the research cant seem to grasp is that most poultry diseases are very serious. Diseases like coryza, MG, blackhead and many many more cannot be tested for, vaccinated against, or cured. Once they get it,assuming they survive, they will transmit it for their entire life. To other quail other poultry wild birds and any other avian they encounter.
Spend a day researching mycoplasma galliseptum, coryza, protozoan infections, parasite transmission etc and keeping up biosecurity really wont seem like such a big deal.
I have a hard time understanding why anyone would risk the health of their birds with so much scientific data available on the subject.