What hidden factors are there in this situation?

In recent years, the sustainability of change agent's programs has received much more attention than previously, both in the United States and in the Third World nations of Latin America, Africa, and Asia. Unless an innovation is highly compatible with clients' needs and resources, and unless clients feel so involved with the innovation they regard it as \"theirs,\" it will not continue over the long term. The importance of sustainability is emphasized by the case of the introduction of American chickens in Eastern Nigeria in the late 1960's by Dr. \"Chicken\" Davis, a U.S. poultry science expert. When Davis arrived in Nigeria, he immediately saw the need for improved poultry raising. Chicken was considered a national delicacy, consumers liked eggs, and the protein in poultry products improved nutrition of the people, but there was a severe shortage of these foods. Village chickens ran wild, eating whatever feed they might nd, and did not provide much meat. Many of the eggs they laid could not be found. \"Chicken\" Davis introduced Western methods of poultry farming: Caged chickens, who were fed imported grain. High-producing, rapidly growing baby chicks were own in from U.S. hatcheries (for several years, I waited for my luggage at local airports while thousands of baby chicks in cardboard boxes were unloaded). Western chicken raising was very popular, and the poultry farming enterprises promoted by \"Chicken\" Davis spread rapidly throughout Eastern Nigeria. During the three years of Davis's program, millions of baby chicks were imported to Nigeria. Protein consumption in the national diet increased, and the small-scale poultry farmers reaped handsome prots. When Dr. Davis retired form the international development agency for whom he worked, at the end of his three- year project in Nigeria, he was awarded a hero's metal by the President of Nigeria. Two weeks later, a poultry epidemic swept through Eastern Nigeria, killing all the imported birds. The wild village chickens were immune to the disease. Within a year of \"Chicken\" Davis' departure, only an unpleasant memory remained of his work. Not a Western chicken survived. What mistakes did \"Chicken\" Davis make from the viewpoint of sustainability of the innovation that he introduced