A report of breeding experiments with "creeper" fowls, in which the leg and wing bones are much shorter and thicker than in normals. This character behaves as a Mendelian dominant, is distinguishable at or before the 14th day of embryonic development, and is probably lethal when homozygous. Creeper X creeper matings produce both creeper and normal chicks probably in the ratio 2 creeper :1 normal; creeper X normal produces equal numbers of creepers and normals. Embryos from creeper X creeper matings have a high mortality early in incubation; 45% died before the 7th day as compared with 4% of embryos from creeper X normal. It is assumed that the difference is due to the death of homozygous creeper embryos early in development. These preliminary data include 33 embryos and chicks from creeper X creeper matings; 71 from creeper X normal.