Lice can usually be seen around the vent, on the legs or under the wings, but I have had a few that I couldn't see any on, but dusted them anyway and within a few minutes they were crawling all over. Mites are harder to see and usually just feed on the bird at night. Check where she sleeps with the chicks, you might find them there. No way to check for worms other than have a fecal test done, but those are not 100% accurate.
-Kathy
-Kathy