The JRT that we've adopted is proving to be dog aggressive, but only towards Gunnar. Gunnar has also displayed some DA in the past, so we're walking a tightrope with the 2 of them. For a couple weeks, the JRT would run after Gunnar as Gunnar would be doing his normal things- patrolling the yard, going and getting a toy to play with. The JRT would be growling, showing teeth, and posturing aggressively. Gunnar would turn around, decide he didn't like the signals he was getting, and let him have it. At first, he'd just roll the JRT, and the JRT would run yelping into the house and hide. The next couple times, Gunnar would chase him down and bite him. He drew blood when he did this, once on the back, once on the shoulder. Same result, JRT runs yelping into the house and hides.
The last week, Gunnar hasn't paid any attention to the JRT. The JRT is still very aggressive towards him. If Gunnar gets excited at all, like when he wants to go out, the JRT will dart from behind a chair and try and nip him while he's not looking. If Gunnar turns around, he'll run away. If Gunnar even runs by him outside, the JRT will run yelping into the house now, with no contact at all. But he'll continue to act out in aggression every chance he gets. Gunnar could easily kill him, it would take one bite and a shake and he'd be done. When Gunnar went after him those few times, it happened so fast, in the blink of an eye he was on him, bit him, and was off of him. It would take the same time for him to kill him. We're glad that Gunnar has finally decided the JRT is no threat to him, and he goes about his business as if the JRT doesn't exist, but we'll always have a heightened awareness. Now, the JRT is held or crated when the other 3 are taken out and given their dinner. Once they are eating, we let the JRT out to eat. Otherwise, with the chaos that abounds around dinner time here, we'd be taking a chance that the JRT would get hurt. Same thing for bathroom time in the morning. Gunnar and Daisy are let out, they come in, I put Gunnar in a down/stay, and let the JRT out. I don't ever think we'll get the JRT to not show DA towards Gunnar, but we can do all we can to prevent opportunities for them to get at each other.
So- would I own a DA dog? Yes, I have 1 and 1 who will give it back if he's challenged. Would I adopt a DA dog? Yes, we did, we had to give Buzz a home. He's really a fun little guy and he gets along with Bruzer and he tolerates Daisy, and has stopped worrying about our cat as well.