I had a problem with botchulism and chickens recently. something got into my quail pen and killed all but 2 quail (killed 24!). I called my cousin, a trapper, who said leave the remains for a night or 2 and he would set traps to catch the colprits. well it worked. We cought a Mink and a possom. but by then, they had already started to rot and the chickens got near where the larvae and ate some. I thought no big deal right? wrong! i had never heard of chickens getting sick from eating maggots so i didnt think anything of it other than the aaaaaweful smell when i removed the quail corpses! YUCK! I noticed a chicken gettin droopy and hanging its neck, not eating or drinking, not socializing and so on. right away we separated it, force fed it water and soon after we medicated it with a broad spectrum shot of 1/2cc. again, i had never heard of botchulism and i couldnt afford a vet bill, and i didnt want it to suffer thats the only reason we medicated it; i avoid it whenever possible otherwise. Well, it survived. I was told because we cought it within the first 24 hours and took necessary precautions that is the only reason it lived at all. unfortonately there was another incident soon after. 2 weeks later one night we got rain so bad it flooded the chocken coop. it had made a mini stream at the base of the coop and the water was coming in so fast it couldnt empty quick enough. in the franzy, that lucky chicken got trampled in the mud and died. the same thing happened to another chicken that same night in another coop/pen we have. so we transported the coops to another location and put "breather holes" on the base of the coop so the water could flow out if it ever happens again.
GOOD LUCK AND GOD BLESS!