Bugbears stealing Farmer Shaina's sheep

Farmer Shaina has noticed that every couple of days, more and more sheep are missing. Her son is the sheephearder and saw 2 bugsbears run off with a sheep towards the lower Paperbark forest. The sheep dogs tried to protect the herd, but the bugbears easily threw them back, even killing one of them.
Farmer Shaina will reward you with a cart or 20 gold, whichever you want
Tarr's Run Bugbear Cave Entrance is an open hole in the earth going down into a small cave Smells of damp earth and mild rotting flesh. Slow drips from stalactites into small pools. No light down here.
Cave Entrance 2 chained Wolves AC 13, HP 11, 10 foot reach of chain, Bite +4 to hit, 2d4+2 piercing If both wolves are hit without being killed, or if the wolves see the party, then they will bark/howl and the bugbears will hide to try and surprise the party
Room 1 – Bones, mostly sheep, but other animals too. If the party investigates the bones and looks through them, Bugbear perception check, DC 15 (+0 perception) If PASS, they hear party and will attack them in Room 2 If FAIL, nothing happens
Room 2 – Couple of moldy bed rolls and straw.
Room 3 – Small campfire with 2 Bugbears AC 16, HP 27, Speed 30ft, Shortsword +4 to hit, 1d6+2 slashing damage, Javelin – 30 feet +4 to hit, 1d6+2 piercing damage
Loot: bloodied sheep carcasses 2 shortswords 2 javelins 13 gold, 5 silver, 9 copper