Working out exactly who was the culprit wasn't very hard as Irwin is too wide to fit through the door of the chook shed. But he had obviously been an accessory to the fact, if not a recipient of stolen goods.
Laying mash (and any chook food for that matter) is very very bad for horses and donkeys. It can kill them. But Guinness and Irwin obviously didn't read the label on the bag. They probably only got a litre or two of the grain and it obviously not enough for them to work out it gave them a belly ache.
So, how did I know exactly what happened? Well, the next morning the culprits came back and we found casing the joint for a repeated offence. Luckily for the chooker moles I have put some mechanisms in place (a brick and a pigtail picket) to ensure that no donkey can open the door to the chook shed again. The door has to stay open during the day so that the chooker moles can get in and out to lay their eggs.
Today I shall move the electric fence so that the donkeys can't get to the chook shed - just to be sure. I don't want an unnecessary vet bill. Lord knows I get enough of them already!