adj. able to bark
There’s a word for you! Eileen Power’s The Wool Trade in English Medieval History (1941) quotes a 13th-century treatise on estate management:
It profiteth the lord to have discreet shepherds, watchful and kindly, so that the sheep be not tormented by their wrath, but crop their pasture in peace and joyfulness; for it is a token of the shepherd’s kindness if the sheep be not scattered abroad but browse around him in company. Let him provide himself with a good barkable dog and lie nightly with his sheep.
Bonus: hinnible means able to neigh or whinny.