RESUMO
A serological investigation undertaken on flocks with depressed egg production. This syndrome is characterized either by a failure to attain predicted production targets or by a fail in egg numbers. The depression in production could reach over 30%. It might or might not return to normal. For a short period the eggs produced in some flocks were smaller, lose color, have poor egg shell strength and many soft shelled eggs are laid. Also, some flocks were suffering from mid respiratory symptoms and increase in mortality with decrease in feed intake. The results revealed that, no obvious correlation was found between antibody to adenovirus, [BDS76 and CELO], infection bronchitis virus [IBV], infections larengotracheitis virus [ILTV], avain encephalomyelitis virus [AEV], Newcastle disease virus [NDV], reovirus or infectious bursal disease virus [IBDV] and this syndrome