Moving to a new place can stop laying, it's stressful, especially a single hen integration.
Those first two eggs?
First one started forming before you brought her home, the second may have been released before she started being seriously stressed.
Those feathers won't grow back until she molts.
A lethargic bird could well be ill...who knows what pests or disease she may have brought with her.
Again, stress from being moved can allow dormant disease to 'bloom' and/or make her susceptible to something your flock may be carrying.
First check her over for bugs:
Have you checked them over real well for mites and/or lice?
Best done well after dark with a strong flashlight/headlight, easier to 'catch' bird and also to check for the mites that live in structure and only come out at night to feed off roosting birds.
Wipe a white paper towel along the underside of roost to look for red smears(smashed well fed mites).
Part the feathers right down to the skin around vent, head/neck and under wings.
Google images of lice/mites and their eggs before the inspection so you'll know what you're looking for.
If you do find some...check out this thread:
https://www.backyardchickens.com/t/1134783/permethrin-spray