dcvelo

If I'm reading this right the dog never even made contact with anyone....

I don't mean to be unfair to the o.p., I know how hard it is not to react in these situations...but if you knew the house you were passing had loose dogs from time to time, it would have made a lot of sense to ease off the pace a little and open up a little distance between riders before passing it so you'd have the option to brake, swerve, or whatever. I do a lot of riding with a group near my weekend place, and that's our standard practice when we approach a house we know to have a chasing dog (of which there are a lot in that area).