Sorry only just seen this thread - worms most likely, check her membranes as well for haemonchis (lungworm). Also get her tested for fluke.
If negative for worms and fluke I would get a blood test done for both Johne's and CAE.
Do they have a salt lick - goats need more copper in their diet that sheep - so a Red Rockie in their housing is a must. (They are now white rather than red, but are still sold under that name). Also lamb creep is not a suitable feed for goats - for smaller numbers a proper goat mix (like Smallholder feed) one is better, but it is pricey. But always feed less than it says on the label...
If you have wethers/castrated males they should be fed only the tiniest amounts of concentrate to reduce the chances of urinari calculii (bladder stones). Best not to feed any, especially not high protein ones.
Unless females are growing and/or feeding kids they also need only small amounts of concentrate feed.