Agressive Jenny

Hi everybody,
I'm looking for some advice and maybe just looking to understand. My DW used to own two Donkey Jacks, but decided for some reason to sell one in favour of a Jenny. Not long after she sold the other Jack to buy some horses. Since she is now only left with the one Jenny and she was firstly pregnant (the Jack managed to leave a souvenier before he left) and she and the mare she bought were a completely mismatched pair. The mare is over 14hh and the Jenny is quite small, probably about 12hh - 13hh and very small built. The mare is a typical pony -stocky as only ponies come.
Anyway, the problem now is the Jenny has become quite aggressive. She lives in a camp with just her foal, another Jenny of about a year old and has now taken to charging anybody who sets foot in the camp. The workers can no longer go and gather firewood in that camp. What can we do? I have no experience with donkeys, but I suspect underneath her aggressive exterior she's a nice little donkey, but if she continues down this path, she may end up someone's dinner...

I have been told that they become protective of thier herd. She may be protecting her baby. Get the baby weaned. Reduce her herd .
I have been told that a donkey in with sheep will bond and then protect the sheep from predators.

Go get your firewood with a longer stick. She's learned to put the run on people. A fellow thought a male donkey would be good for his gas station business. He built a nice grassy paddock, good shelter. Donkey ran toward him to greet him and he ran from the paddock. His son went to feed him. Again donkey ran to greet him. Son ran out the gate. Donkey soon figured out how to get rid of people.