I’ve been using wool battings for years. Hobbs Wool and Dream wool.
i have never prewashed a batting of any kind.
i always launder my finished quilts - in the washer, normal cycle, toss in dryer, normal settings. - I’ve never had a less than desirable outcome; the quilts come out of the dryer soft, lofty, fabulous
the ones I’ve used ( Hobbs and Dream co. ) allow r” between quilting lines ( the package should tell you the recommendation for quilting)