Thank you for the additional information.
You've only had them 3 weeks. As I mentioned previously, if a fecal float is not doable (a lot of vets simply will not look at chicken poop - not sure why but they won't) then I would consider going ahead and de-worming.
I would also give her extra...
I'm glad you were able to get rid of the lice.
For her, I would try giving Caltrate (1/2 tablet) once a day for 5 days to see if that makes a difference. I know some will suggest to give more than 5 days but you can overdo calcium.
Hopefully this will help firm up the egg shells.
Where...