I used counter-conditioning/ desensitization (CC/DS) and look at that (LAT) to teach my dog! Basically, you teach your dog to look to you anytime he sees or hears a squirrel. It does take time – we’ve been working on it for 1 year 4 months now – but it makes for good results in most dogs.
Here are some links on CC/DS and LAT (X, X, X), and here are some on using CC/DS for squirrels (X, X).
Training impulse control can work wonders too. A dog that can control his impulses is much less likely to go bonkers when a squirrel appears on a walk. Again, impulse control takes a long time, but I personally find it’s worth it in the long run. (X, X)
Don’t let your dogs stalk or chase squirrels/small animals when you aren’t walking. If you absolutely want to let them chase small animals, make a clear distinction: NO HARNESS = Allowed to chase versus HARNESS = Not Allowed. The best way to ruin your training is to contradict yourself without noticing.
Hope that helps! I know how frustrating it is to have your dogs lose their mind at every single small animal. Hang in there! -C