I see that someone mentioned the heat from the deep litter....
I had been doing this in our barns, especially in my chicken pens to keep the chickens warmer in the winter.
Well this year in Feb we had a double barn fire, we had a very large barn and then a smaller open air barn with a closed building built into it that we used as a milking/treatment room and quarantine bay.
It was horrible they say it must have started in the big barn and because of wind it spread to the second one. They were both engulfed very quickly, I had gone out to check on my daughters calf at around 10pm and at 11pm my husband noticed flames outside I ran out but it was too late.
We lost 14 goats, 10 does that were confirmed pregnant and due in March, 2 large buck brothers that I had raised by bottle from birth that were my first goats I ever had, they were from a birth of 5 kids and only weighed 2 pounds each, they were not thought to live long but I nursed them and loved them and they were both almost 200 pound Oberhasli males.
We also lost my daughters calf, well she was not a little calf anymore lol we had raised her from birth around 70 lbs I think and she was 300 lbs.
It was the most devastating night of my life, and the hardest few weeks following as I tried to clean up and prayed over each animal that they had not suffered greatly.
Anyway sorry this got away from me, but I was told by arson investigations that they believed it was spontaneous hay combustion. Basically they said the deep litter got too hot and caught the bedding on fire.
Now our barns did not have electricity, so no heat sources from lamps or wires were even a part of it.
Personally I think it was arson I had been doing deep litter for years, cleaning out once a year, but we were renting our farm and the day after the fire my landlord said he didn't want to renew our lease which was up 2 months later.
He's a bad guy I really wouldn't put it past him to kill all my animals thinking it would be easier for us to find a new place.
But anyway, I know where we are now is much better and we are much happier here.
I still wonder though if the deep litter heat really could have started that fire? There were no chemicals or gas or anything like that in there either.