A Case Of Arson

There was a fire the other night in our town - 150 hay bales burned down, right next to a cowshed. The cows are fine, most likely because the fire department was alarmed early enough by local residents (our town is about 500 meters away from the shed).
Because there was not enough water they had the burning bales burn down under control and secured the others.

At first everybody thought it was a spontaneous combustion of the bales which can happen when the moisture content in the bales is too high, but no, they found evidence some idiot set the bales on fire. Just why? And if burning bales are so very funny - any thoughts about the cows right next to the bales?

Here's a look at the bales from last year (same location).

Sorry, if I use the wrong English words. Arson and spontaneous combustion etc. have not yet been in my English vocabulary and I had to look them up.

20:45 CEST 20,2°C