Not always Dot, but they often do run in pairs or more. Not really sure about whether you should brake or not, makes sense just in case I suppose.
I remeber being out in the field one summers evening, and 3 roe deer came running out of nowhere, looking like they were being chased. My stepdad had been scaring me with tales of the beast after the neighbour found a deer with its leg bitten clean off, only a few days before. I ran as fast as I could all the way back home.