What about installing an electric/invisible fence inside your fence/yard? They are rather cheap these days. Many of my neighbors have their dogs in their yards this way, just not the regular fence and the invisible at the same time.

My experience is that once they figure out how to get up and over, they will continue! Yikes.

I personally would do a higher, deeper fence, but that may be too darn expensive.

What about a surrounding pen? Wide, tall, etc. but not the kind you can get out of. It sure beats staying inside the house. Maybe you could build one that has a little roof to protect the pups from the rain.

Good luck. I am so glad neither doggie got hurt. I bet you were/are so upset. I would be too! Yikes x 1,000,000!