If she is unable to pay the amount to restore your flock and repurchase a donkey comparable to your donkey (similar age etc), she may have homeowners insurance that would cover this for her. Personal liability is designed for this sort of thing. You should not "profit" from the situation, but you should be made whole and be put back in the same situation that you were in before the dogs got loose. And to be fair, you do not know for sure that it was her dogs whittling down your flock, it could have been feral dogs, other loose pet dogs, hawks, raccoon, fox, coyote etc ... the possibilities are endless!
Yes her dogs should be chained, but it is just a matter of time before they get out again even if she decides to chain or otherwise confine them.
I personally do not feel that she should have to foot that entire bill to build a state of the art coop, fencing etc, and actually doubt that she could legally be forced to do so. But reasonable compensation should certainly be paid.
The county lineman had damaged one of my pasture fences and my own goats escaped, who then got in to my own vegetable garden and orchard, obliterating every edible thing in sight. 4 wonderful apple trees were destroyed, as well as a summers whole growing season. The insurance company just could not understand how I came up with the figures I did, and they would only pay what it would cost me to purchase seedlings and young trees from a nursery. So be prepared to accept a minimal amount.
My personal approach would be to rebuild the coop close to the house, and design a better predator control system. Establish a secure coop with fencing, surrounded by an electric perimeter. If you are not prepared to shoot dogs or coyotes on your property, there are plenty of gun toting boys who would jump at the chance. Collar or no collar. Good luck in whatever you choose, it sounds like your neighbor is a good person who wants to make it right. Hard situation to deal with, but there are good solutions available to you.