My french lavender was plucked off its pot by birds (I saw feathers near the pot) and only the roots remain. Is there any chance they'll grow back again or should I just replace them?
You can always let it try to grow back. You are out nothing but perhaps some small effort if it fails to come back. Plants can surprise you!
I have had French Lavender come back from the roots, but it was older and planted in the ground.