Root and blast the hell out of them, typical wizard style. They hit hard and
fast and it can be tough to get off a good spell while they are doing this.

If you are in a group with a cleric(really just you and a cleric would be
perfect) have the cleric cast spook the dead on it. When it succeeds the
crow will turn and run and you can blast it to hell.

If you are looking for solo critters near the Miller farm and the crows seem
to be a bit tough then I suggest killing grizzlies. They are easy to solo
and are worth decent exp as well they run when low on health which is always
a bonus when soloing.

Yours,

~Aereuss Ravins of Tarew Marr and one time resident of the Miller farm.