My two dogs do the weirdest and frankly, most annoying thing and I need them to stop.

It's mostly in the late afternoon to nighttime that they do this annoying thing. It's like they get bees in their bonnets and they make a mad dash to the door/ outside/ other room, all hysterical and barking but there's literally nothing going on. They will do this several times an hour, again for no reason.

The one is nine years old and the other is 11 months old. They have a garden, doors are open for them to come in and out all day, they get new toys all the time, I take the puppy to the park twice a month (it's all I have the time for at the moment) for a huge, one hour long run/ walk/ throwing balls/ playing with other dogs/ etc.

So I don't understand why they do this but they get all the other animals nervous and anxious when they suddenly leap up and run and bark as if the house is under attack. Several times an hour.

Any ideas on how I can stop this? It drives me crazy.

*They have a large garden to play in. Yes they get enough toys, in fact they got FOUR new ones in the last week alone (one is a cute banana where you can stuff treats in and they have to try dig them out). They play with each other daily and have zoomies and all sorts. I also play with them. I don't know if it's understimulation.