“…Reported results on hatchability of in ovo delivered FA and EO, are quite variable in the few available literature. Increase ranging from 20 to 29% ( Gouda et al, 2021 , 2022 ), decrease ranging from 2 to 22% ( Abdel-Fattah and Shourrap, 2013 ; Abdel-Halim et al, 2020 ) or unchanged hatchability values have been reported for in ovo delivered FA ( Nouri et al, 2018 ; Ismail et al, 2019 ). Similarly, the few available results on in ovo delivered EO have also reported increase of about 14 to 37% ( Nadia et al, 2008 ; Sulaiman and Tayeb, 2020 ) or no effect of in ovo delivery of EO on hatchability outcomes ( Saki and Salary, 2015 ; Toosi et al, 2016 ).…”