How old is she? Is she normally with a flock? What kind of coop, run, bedding, feed? --- Sorry, you said she is four weeks old.. so.. worming does not apply at all. Worms are not the issue... and parasites shouldn't be either.
Has she been in the house? Indoors? Has she gotten cold (before you brought her in)?
If you have been hand feeding her, making her a pet... she may peck you less and less. Will she eat without you feeding her? Is she lethargic...?
What are her "sick" symptoms?
Use the search here... on BYC...
How does her poop look? If you search "normal poop" you will find threads that give a link to a UK site that shows pictures of all the normal kinds and some not normal kinds of poop. Good link to check out.
Best of luck.. if she is eating and drinking that is very good... if they eat "wet" food... if you wet their food and make a mash out of it... they will sometimes "gape".. open their beak to clear their throat -- I think the wet, mushy food gets stuck more... in my opinion. If she takes a drink of water after eating... that should wash the food down.
Take care...
