I have owned my donkey (wild burro) for over 3 months now. I have noticed that she is eating charcoal. She is let to out to run my property at night and I have noticed that over the past few days charcoal has gone missing from my fire pit. I thought I was just mistaken. BUT tonight I went out to check on the animals and that was when I found my donkey eating the charcoal. She has a mineral black, I feed her top hay and grain. And she is also let lose to forage for other natural plants that she would eat out in the wild. I have never had a horse eat charcoal, could she be needing something that the charcoal offers that the salt block or grain is not giving her.