Dropped egg production, soft shelled and shell-less eggs associated with appearance of precipitins to adenovirus in flocks of laying fowls.

Two outbreaks of dropped egg production and production of soft shelled and shell-less eggs are described. The outbreaks were selected from a larger number of flocks with similar problems in the field. The drop in egg production was closely correlated with the appearance of precipitins to adenovirus in the laying birds. Birds were also infected with Mycoplasma synoviae. A number of other infectious causes of production problems could be excluded in these outbreaks. In particular infectious bronchitis was not a factor and, in contrast to experiences following infections with this virus, production recovered nearly completely within 6 to 10 weeks. The observations suggest that in the field infections with adenovirus may cause production problems as serious as those caused by infectious bronchitis virus.