Two flocks of turkey breeders experienced an increased mortality and high culling rate in the first weeks of egg production. The majority of dead and culled hens had cheesy core in the cloaca and vagina. Postmortem examination revealed fibrinous pseudomembranes in the vagina and cloaca. The thickness of these membranes posed an obstruction to egg passage leading to internal laying and egg peritonitis. Swabs from cloaca and vagina produced numerous colonies of only E. coli. Investigations of this unusual vaginitis showed that these two flocks had a higher number of immature hens with present hymens, and insemination crews mistakenly inseminated all hens in which they were able to evert the cloaca. Breaking the hymen with an insemination pipette created a wound and developed extensive infection with E. coli bacteria.