Abstract Eggs with olive colored yolks, commonly called by the trade “grass eggs,” “alfalfa eggs,” “green rots,” etc. are sometimes found in large numbers early in the spring when the eggs are candled at collecting points. Buyers have held the opinion that these were produced when the hens ate large quantities of grass, alfalfa, or green wheat. When the contents of the egg are examined the white appears green tinted and the yolk has a greenish brown or olive color. The density of the yolk color gives the entire egg a green appearance when candled. The strong flavor and unnatural color condemn these eggs for table use. Many buyers put them in the second grade or discard them. Very little information is available relative to the cause of olive colored yolks. Pennington (’18) has the following to say about “grass eggs.” “Sometimes eggs with olive colored yolks are found. These reflect . . .