One day this winter I found a chicken dead in the coop.
The night before, when I closed up the coop, all eight birds were roosting and looking fine. Nothing out of the ordinary.
The next morning, when I opened the coop for the day, all the hens were clucking away and bustling around like normal.
It was only later in the day when I brought the chickens back inside that I noticed the dead bird.
The hen was collapsed on her side on the floor at the back of the coop. Eyes closed. Body limp and floppy. She showed no obvious signs of trauma: no blood, no injury, nothing stuck in her mouth or throat. Her comb and wattles were cold and pale. But her abdomen was still slightly warm. There may have been a pulse when I checked under her wing; it may have been the pulse in my own fingers.
In the weeks that followed, no additional birds died. All of the chickens kept on doing their regular happy chicken things.
The death was weird and disconcerting.
Causes of Sudden Chicken Death
I’ve done some reading and some talking with other chicken owners since that time. Apparently, it’s not entirely uncommon for this sort of thing to happen.
Heart attack: Sudden death is a pretty well known syndrome among fast-growing broiler chickens. The birds die with a “short, terminal, wing-beating convulsion” and often flip on their back. The cause is a heart attack. Recent research suggests the heart attack is triggered by stress; the chickens seem predisposed to heart attacks because of microscopic lesions in the muscle of their hearts.
Egg-bound: Layer chickens can die if a fully-formed egg gets stuck somewhere between their shell gland and vent. Possible causes: the egg is too big, there is injury to the reproductive tract that blocks the egg, or the chicken has hypocalcemia (calcium deficiency). Overweight chickens are prone to getting egg-bound. So are young hens that are pushed to lay before they’re fully mature. Egg-bound death isn't sudden; there are signs that a hen is egg-bound and a few steps you can take to move the egg. However, the blockage often isn’t discovered until after the chicken is dead and owners can be caught by surprise.
“We all got to go sometime”: Accidents happen. A chicken could ingest something poisonous. One bird could jump down from a high roost on to another bird. Heck, a chicken could just run into a wall too hard. Once I had a chicken get a single toe stuck in the edge of the coop loft and hang upside down for a couple hours before I found her. The bird was fine once I got her unstuck but the point is: weird accidents happen.
How important is it to find an answer when a chicken suddenly dies? That’s completely up to you. Like with all things chicken-related, it comes down to paying careful attention to all your birds. If you have reason to suspect contagion or disease, or notice abnormal behavior in other chickens in the flock, get the dead bird examined immediately. If the rest of your chickens keep doing their happy chicken things as normal, maybe it’s not a high priority. As one chicken owner put it: “Where there’s livestock, there’s deadstock.”
The only unsettling thing about having no obvious reason for the death is there’s nothing concrete you can change or improve as a matter of prevention and protection for the rest of your birds.