Yay Murkrow is going to die!!!
Tbh I havn't played LC in a while, since Gen 6 came out, and I'm probably not planning too XD. I still remember Murkrow, and I'm guessing its even more of a force now :x
In all truthfulness I can't think of any hard counters off the top of my head.
Physically Defensive Pokemon like Slowpoke are decent checks I suppose - Slowpoke has good recovery, access to status and can tank all of Murkrow's moves barr Sucker Punch which requires Slowpoke to attack, so it can just go around playing mindgames. HP Grass is too weak to do enough damage, though someone do the calcs for me.
Scarf Mienfoo is a way to Revenge Kill.
A healthy Chinchou can take a HP Grass and retaliate with super effective STAB
The best way to take down that set imo would be to have Stealth Rocks up on the field, bring in a defensive wall and try force it to kill itself through residual damage. Very few things can take it on safely, generally being defensive walls, though I suppose random things like Scarf Snover, Scarf Mienshao, Scarf Shellder can surprise it and revenge kill it, and priority from Pokemon which can tank Sucker Punch also helps take it down. Tanky Rock Types can survive a HP Grass and retaliate with Rock STAB, as goes for bulky Electric and Dragon types I'd say. Anything that outspeeds, and resists Sucker Punch is a fine revenge killer as well.
So basically, use it's SR weakness, lack of recovery on that set, high amount of recoil and low defensive against it. :>