Which dog is showing aggression towards other dogs - is it only to to other dogs or his littermate aswell?
I know people advise that is not always good to get 2 pups from the same litter at the same time, but don't know if you can say it is categorically the problem or if something else is contributing.
Why do you take the food bowls away? Do they guard food? Are there any other problems apart from aggression to other dogs?
I am no expert but have heard that it is good, to walk separately and train dogs separately, but I don't know if that has to be forever.
I suppose the thing to do is work with the dog that is behaving like that to the other dogs alone. He is probably not being aggressive, he is most possibly anxious.What has the behaviourist actually told you to do to remedy the situation?
For what it's worth this is what I would do. I would tale him somewhere where thetwo of you can sit and watch other dogs and people from a distance. Whne he sits calmly and watches give him a treat. You could then take him a little coser to watch, where some dogs may pass by. When you see them approach, have him in sit or down and show him the treat to get hom to focuson you rather tahn the dog passing by. If he remains clam and focused treat immediately and praise. Even if he looks at the dog but reamins calm, treat immediately. Keep working on this until he is successfully letting other dogs pass without becoming aggressive. Then progress to walking him past other dogs - show him the treat as the dog approaches, get him focused on you and walk past treating and praising as he remains calm. You oculd use a click and treat as well.
It sounds very simple, but if you remain calm and reward the good passes and ignore the bad ones. My cheeky girl makes a fuss walking past humans, or when humans walk past the car. Now as soon as she walks past people or people walk past the car, she automatically looks for her treat.
I also would stop taking the food bowls away, especially if food guarding is not an issue. If it is an issue, everyone else has given great advice about dropping extra food into the bowl. It is advice taht has definitely worked for us.
I would also consider speaking to a different behaviourist - you have 2 dogs, the best advice would be how to make life better for both of them. It doesn't sound in my limited experience, as if, at the moment, there is nothing that cannot potentially be resolved. I think rehoming one, would be a lst resort, rather than something that is suggested at the outset
. Only my opinion - I nay be wrong though.