Lots of possibilities to consider here; tough to say without being able to see the two dogs interacting in real time. This is where a qualified dog trainer could help you diagnose the issue, if you could somehow scrape the cash together.
-
The poodle NEVER interacts with other dogs, ever? How does the poodle react to unfamiliar dogs in neutral surroundings (i.e., not in the home, just out and about?). It doesn’t sound like the poodle enjoys extended interactions/playtime with other dogs, but are random encounters with other dogs peaceful? Are good dog manners observed by all (both the poodle and the other dog appear calm, direct eye contact is avoided, polite butt-sniffing occurs or dogs ignore one another entirely, etc…)
-
Take Toby and the poodle to neutral territory, with some reasonable distance between them. For example, have you and your father walk the two dogs on opposite sides of a quiet residential street. How does the poodle react to Toby? (Ignores Toby? Keeps glancing at Toby periodically? Watches Toby warily and/or stares? Barks his head off at Toby anyway?)
-
Take Toby and the poodle to neutral territory. Have one person keep Toby at a certain spot and do not allow Toby to wander from the spot (use a short leash). Start with the poodle very far away from Toby, such that the poodle is not barking or displaying any signs of nervousness about Toby. Calmly walk the poodle towards Toby. As soon as the poodle shows signs of excitement/tension, or it feels like the poodle may start barking, immediately move away. What is the minimum distance that must be maintained to keep the poodle calm?
-
Repeat #3, but inside the home (assuming you have a big enough room, long enough hallway, etc…)
-
Does the poodle only bark, or does the poodle also growl, bare teeth, and try to nip/bite Toby?
