Effect of Marek's disease vaccines on interferon and toll like receptors when administered in ovo.

•The effect of MD in ovo vaccination on the transcription of IFN, IFN receptors and TLRs was influenced by the vaccine and the tissue evaluated.•HVT increased IFN-γ and TLR-3 transcripts in the spleen and lung.•CVI988 downregulated several of the studied genes and only upregulated TLR-21 in the spleen.