meat bird hatching eggs + rooster issue

[VanUnamed]

17 eggs are developing at day 16, so my rooster did his job.

 

[VanUnamed]

....bad news... 6 out of 8 chicks got ill with marek, and i had to kill them. i don;t understand where this strain so infections came from.

 

[Molpet]

....bad news... 6 out of 8 chicks got ill with marek, and i had to kill them. i don;t understand where this strain so infections came from.

terrible and so sad

are you sure its mareks and not a nutritional deficiency ?