Apart from domesticated birds which are kept or bred for various purposes, many species of birds are also popular as pets today. People have used birds since ancient times to convey messages or simply for their attractive appearance. Like other domesticated animals, birds have been selectively bred for centuries to pass on desirable traits, which in some cases has had undesirable consequences. The biggest problem that occurred was the reduction of genetic diversity and inbreeding, which led to the occurrence of hereditary diseases. Genetic testing is a simple and non-invasive tool that is now used in many fields and institutions, including veterinary clinics and the breeding industry, and has numerous applications. In birds, they are used primarily for sex determination and detection of disease or desired phenotypic traits, all with the goal of maintaining and improving animal welfare.