What you need to know:
*Appears at: 75-100% difficulty level (or 85+)
*HP: same as the normal chickens
*Tries to fly towards the player
*If it gets too close, it explodes with a loading time of 0,5-0,75 second(s). While loading, the chicken cannot move.
*In this time the player has to choose: Kill the chicken or get far enough in time to not explode with the chicken.
*If the player cannot kill the chicken or get away in time, he/she dies.
! Important !
The photos are only for informative reasons. I did not specify the exact texture of the chicken/explosion.
Sorry for my poor editing skills.
Comment down below if something is wrong, I hope you like my idea
(Edit: At attack formations, these chickens could come from both sides, like 2-4-8-10 Self-Destructing Chickens for some (each) waves, depending on your difficulty level. Rookie, Veteran, SS Hero etc.)