Agree with others. First & foremost, geld your Jack! If you're not experienced & knowledgeable and planning to breed. Jacks can be more of a handful than stallions & known to be aggressive. Don't keep him with goats or other small animals he can harm, if he shows any aggression towards them. He can live happily with your horses, or cows or other large beasts.
The stud jack where I got my donkey for spent a lot of time with the owner's Great Dane. They were good mates & used to play together. They were both lone animals otherwise, the dog being the only dog, the Jack kept alone because he was aggressive toward geldings &... inappropriate with Jennies... probably because of his social starvation. One day though, Jack was in a foul mood & when Dane came to say hello, he picked him up by the back, shook him a few times & tossed him to the other side of the paddock. End of dog!
My own donkey(gelded young) had never shown any aggression(except chasing away a few of my boyfriends when I was a teen!) when I brought him back to live with me. I had puppies. They were playfighting in the paddock, oblivious to their surrounds... until suddenly they realised, too late to run, that there was an angry donkey bearing down on them, ears back, teeth bared... I was too far away to do more than yell, imagining pulverised puppies! Don't know if the yelling had any effect, but donk charged them, then slammed on the brakes, reared over their heads & brought his hooves down on... either side of them. Then walked off as if nothing happened! I reckon he was warning them that he was to be respected around these parts. He never showed the slightest inkling of aggression towards them ever again.