Our understanding of skeletogenesis, myogenesis, lineage, embryonic patterning, craniofacial development, vasculogenesis, angiogenesis, wound-healing, immunology, and mechanisms of teratogenic effects has also progressed significantly as a result of studies on the chick embryo. Many mutations that result in developmental abnormalities are available. These have been, and continue to be, extremely valuable tools for the study of developmental processes. Chicken eggs are plentiful, inexpensive and extraordinarily convenient. Large numbers of eggs can be incubated at one time to obtain embryos at precise stages of development.
Chick embryos are much cheaper to maintain and study than mouse embryos.
Most institutes' facilities for maintaining and growing transgenic mice are already inadequate, and it is inevitable that this shortage of space will become more severe, even if funding is diverted into expanded infrastructure. The chick represent the model system which most resembles other higher vertebrates while still permitting experimental intervention in ovo. As such it represents an important complement to mouse model systems. This system is already being used to analyze many gene products that control general processes, such as cell-cycle control, chromosome structure, etc. Rapid advances are being made in chicken transgenics, ES cell technology and the cryopreservation of sperm, blastdisc cells, primordial germ cells and ES cells.