Hi, Im new to this forum and was wondering if anyone can help. I have two
male pups (border collies) now 17 weeks old, up till now they have been very well
behaved, but now when we go out for walks they bark at the sight of humans and if another dog appears they go ballistic, i have tried getting people to get down on their level to talk to them, but one of pups even tries to bite them, quite worrying.

Are these two pups from the same litter? Have you had dogs before? I fear not, as taking on two border collie pups at the same time is not something many people would do if they knew what they were letting themselves in for.

I'd walk them separately, you may find each behaves quite differently without the other dog to back them up.

Also, unless you are an experienced dog owner, training classes - again taking one dog at a time. If the class is weekly, alternate them, and practice at home, both separately and together.