The cider vinergar is for "healthy gut" and general well being..to enhance right acid balance for growth of the healty bacteria..or something along those lines.. ::)
While you girl is sniffiling I would used garlic first as it does have mild medicinal properties against bacteria...ohh..my brain this morning..cannot find right words,,,oh,,anti..something like antibiotics..
and as she start feeling better..then cider vinegar is good..keeping the pecker up..and you can give that regurlarly..but it is good every now and then to give a period just plain water..
all good things in moderation..
.but if you start seing discharce or change in appertite and/or droppings....off to vet..