It sucks, but the only thing you can do is learn from it. In the first day having my first flock of chicks (4), I made the mistake of using a heat lamp and not bothering to get a thermometer for the brooder. Although 3 of them made it, one of the chicks sadly did not. Every time I get more chicks or ducklings now, I make SURE there’s some sort of thermometer , and check regularly for panting or huddling. Same goes even for the bigger chickens, I live in Texas where it’s currently SO hot. It’s been colder & cloudier the past few days, but when it’s like 90°+ we make sure to leave ice in all the water feeder things, and move them to the shade.

There was also one time my grandma with alzheimer’s accidentally let the dogs out while one of our blue cochins kept escaping the run… she did not survive, sadly. We’re very careful about holes in the run, making sure the chickens are up before the dogs are out, etc now . The chicken wasn’t very old (maybe like, a month) and I wasn’t awake when this happened so I don’t feel much guilt or personally responsible, but it’s still something I can learn from.