During two experiments hens are fed with diet supplemented with or without 10 ppm of Bacitracin or 0,5 ppm of Flavomycin. Both increase retinol transfer from diet to yolk. Differences are not always significant. They are concerning almost a more important percentage of eggs whose yolks contain between 500 and more than 700 IU of vitamin A (66,6 p. 100 for Bacitracin supplement; 80,9 p. 100 for Flavomycin supplement and 45 p. 100 for control). Each additive increases hepatic storage and serum level of retinol but not significantly. Transfer of vitamin A from diet to yolk is between 12,1 p. 100 and 24,0 p. 100 regarding individual variations. There is no influence from the strain. Warren or Dekalb, used.