Abstract THE nature of the carotenoid pigments (xanthophylls) which are deposited in the beak, shank and adipose tissues of chickens and in the yolks of eggs, the methods of their measurement, and the effects of antioxidants upon their utilization, have been studied recently by Marusich et al. (1960); Bunnell et al. (1962); Sullivan and Holleman (1962); Madiedo et al. (1964a,b); Bornstein and Bartov (1966); Bartov and Bornstein (1966), and others. Following the synthesis in quantity, according to the method of Isler et al. (1958), of β-apo-8′-carotenal and canthaxanthin, crystalline samples of these materials became available in pure form for studies of pigmentation in broilers and in egg yolks. The present report deals with comparisons of β-apo-8′-carotenal, canthaxanthin, and a number of natural sources of xanthophylls for pigmentation of egg yolks when added to (1) a standard laying diet containing yellow corn and a low level of alfalfa meal, (2) a practical . . .