Firecrackers are the most effective way to disperse large pack of dogs. I carry it on hikes.
Lighter is also quite good weapon. Not the BIC type, more like a small blowtorch for melting copper and other metals.
Pack does not attack fast (as single animal would). They have hierarchy, and first try to encircle victims. The situation will literally unfold in "leisure manner", they have overwhelming force, and are not in hurry. They also go first after smaller targets (children, your dogs). You will have a lot of time to watch.
Often you find some semi-safe spot (tree, high ground), but can not leave.
The danger is not to get bitten a few times by alpha dogs, but to let attack continue long enough, you get overwhelmed and all dogs join in.
Do you hike in Chernobyl?