This is such a horrible attack. I'm glad you found out who the owner is. What sort of owner is she if she can't keep control of her dogs? Why do people have such big dogs if they can't control them? It's all very well being sorry but it's a bit late for your poor wether.
My rare breed chickens were attacked by a Dalmation a few years ago. Apparently my poor little Lavender Pekin was tossed up in the air several times by it. The dog was renowned for escaping and causing mayhem. The owner said 'sorry'.
I agree with this - I have a rescue Doberman who is not safe with any livestock, and yet I have sheep and my neighbours have sheep and cattle. We spent a large proportion of our renovation budget on installing a mesh 7 foot fence so Dobie could have freedom on our land but our neighbours would also know that he would absolutely never cause them an issue. Apart from wondering if we were going to keep llamas or emus :-DDD, neighbours have been very appreciative (and actually the fence is very useful for lambing as we have split it so he can still have part and lambing ewes have a different part).
Our action was extreme but it really does reflect the degree of responsibility we felt to protect both our own and our neighbours animals, but also our dog's life, and quality of life.