design: Viral nucleic acid was extracted from 200 ul of the tissue homogenate using the High Pure Viral Nucleic Acid Kit (Roche Diagnostics, USA). Circular DNA in the extracts was preferentially amplified using rolling circle amplification (RCA) with the Templiphi 100 Amplification Kit with DNA Polymerase Phi29 (Cytiva Lifesciences, USA). 15 ul of viral nucleic acid extract and an equal volume of RCA products from all organs and cloaca swabs of individual birds were pooled to represent a single sample per individual bird. All these were then used to construct DNA sequencing libraries using the Illumina DNA library preparation (M) tagmentation kit (Illumina, USA). These libraries were sequenced on an Illumina NovaSeq X Plus sequencer (Illumina, USA) at Psomagen Inc. (USA).