select sno,Branch,
(select count(transferbirds) from K_RT_RetailsDetails where branch in (PN.sno)) as Totalbirds,
(select count(noofbirds) from K_RT_WarehouseDetails where branch in (PN.sno)) as Meatbirds,
(select count(noofbirds) from K_RT_MasterBirdsTransferDet where frombranch in (PN.sno)) as TransferBirds,
(select count(mortality) from K_RT_DailyEntry where branch in (PN.sno)) as Mortality,
(select count(noofbirds) from K_RT_BirdsTransfer where branch in (PN.sno)) as Tobranchtransferbirds
from K_RT_MasterRetailStores PN
I have guess that you want count of total birds so i put count in subquery as per your requirements you can use count, sum, top 1 .
Here the logic is whenever you uses subquery , the result of subquery should have one and only one, not more then one row.
Please comment me if you want more detail.