Lonely Donkey?

I have a chance to adopt a female donkey (jenny?). We have a barn that could be fixed up for her, and she would live in the pasture where the chickens free range. We've had issues with dogs, and my justification for taking her is that she would be a deterrent to them. Would she be lonely? Could she be with the cows (three steers)? Should she have a friend, maybe (justification again) a goat would do? They get hay that is sometimes a lesser quality, and I know is not acceptable for horses, but don't know if Donkeys require the same. My cows avoid the toxic plants (I ran around madly pulling poke and datura until I realized they wouldn't touch them, or the thistles).

Thanks,
Margo