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Summary Crosses were made by means of artificial insemination using semen from capercaillie (Tetrao urogallus) on chicken (Gallus domesticus). Semen samples were collected from 22 birds and within a few minutes inseminated into a group of 25 meat ‐type virgin pullets. Each pullet was inseminated about once a week, always with semen from a new male. A total of 1418 eggs were incubated, of which only 8 eggs showed embryonic development. Out of these, three eggs hatched at the 24th day of incubation. The eight cases of embryonic development, all originated from five inseminatios from a total of 136. Four of these inseminations and seven of the eight embryos, all originated from only one of the 22 capercaillie males used for inseminations. Male no. 7 is the sire of the three vigorous hybrids. The results of this trial support the hypothesis that an incompatibility exists between the oviduct of domestic fowl and foreign sperm. Similarly the confinement of successful fertilization to only five groups of full sibs and the fact that seven out of eight embryos were sired by one male suggests a genetic component.