One of the oldest problems of concern to tlie eggproduciny industry is the occurrence of blood spots in eggs. While many dietary factors have been reported to affect t?ie incidence of eqgs containing blood spots, these relationships have not established the direct cause of this abnormality. Studies were conducted to determine the relationship of the vascular integrity of birds to the percent of bloodspot eggs they produce. Both a nor.raal conniercial strain and an experimental strain producing a high incidence of bloodspot eggs were examined. Four feeding trials vrere conducted in v/hich the progeny from hens of both strains treated V7xth a copperdeficient diet Vv'ere subjected to the stress of g-aminopropicnitrile (BAPN) toxicity. Production, fertility, hatchability and liver copper levels v/ere used to determine the XX blood-spot strain are most notev;orthy. The relationship of these characteristics to the high incidence of blood spots has not been established at this time.