Chromatography on carboxymethylcellulose of the trichloracetic extract "F(1)" of chicken erythrocytes nuclei, yields two histone fractions: F(1)-cF(1) the very lysine-rich histone and F(1)-cF(3), the fraction specific to erythrocytes.Aminoacid analysis and disc electrophorosis on extracts "F(1)" demonstrate that specific histone fraction F(1)-cF(3) occurs in smaller percentage in the early stages of chicken development; it increases from 6% (by weight of the total DNA) in 3 days old chicken to 16% in 21 days old chicken. But the percentage of F(1)-cF(1) fraction (8% by weight of total DNA) remains constant in the same conditions.