“in Thale they were formerly obliged annually to throw a black cock into the Bode [River]; for if they omitted to do so, someone would certainly die within the year”

“among the Votes of Joenpera [in Finland]…before building, the ground would be worked while holding a black rooster by the wings, because it was said evil spirits feared the color black.” Black is a protective, warding color, repelling evil.

From chicken magic in folk tales and lores

https://www.witchesandpagans.com/pagan-studies-blogs/hob-broom/chicken-magic-in-folktales-and-lore.html