text: Egg shell color is caused by pigment deposition during egg formation in the oviduct and can vary according to breed, from the more common white and brown to pink or speckled blue-green. Although there is no significant link between shell color and nutritional value, there is often a cultural preference for one color over another. For example, in most regions of the United States, eggs are generally white; while in the northeast of that country and in the United Kingdom, eggs are generally light-brown. These habits may be associated with perceptions of greater purity in white-shelled eggs or greater wholesomeness in brown-shelled eggs.