Post-implantation mouse embryos are essentially unavailable for experimental manipulation, and are not suitable for ex utero culture for more than a few hours. By contrast, the large and robust chick embryos are accessible during the stages when most important developmental decisions are taken so that a large variety of methodologies can be used to analyze the genetic regulation of a many different developmental processes. 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.