TABLE 1.

Summary of the six treatment groups in this study, showing the combination of monochromatic lights and vaccination strategies.

Treatment group	Light treatment	Vaccination method and age	Sampling age
Light not vaccinated (LNV)	Green monochromatic light	None	ED18
Dark not vaccinated (DNV)	Dark	None	ED18
Light in ovo vaccinated (LIV)	Green monochromatic light	In ovo (ED18)	PHD7
Dark in ovo vaccinated (DIV)	Dark	In ovo (ED18)	PHD7
Light post-hatch vaccinated (LPHV)	Green monochromatic light	Spray (PH1)	PHD7
Dark post-hatch vaccinated (DPHV)	Dark	Spray (PH1)	PHD7

The main groupings were based on biostimulation during incubation and the method of vaccination. The experimental birds were administered vaccines either in ovo on embryonic day 18 (ED18) or day 1 post-hatch (Day 1). Vaccinated birds were sampled on post-hatch day 7 (PHD7).