SafeGuard Liquid Goat Wormer is good to worm in general, and treats gapeworms. Very few antibiotics that treat respiratory diseases are available without a vet. Tylosin powder for the water may be available online from a pigeon supplier, such as Jedds.com. Feedstores may sell refrigerated antibiotics such as oxytetracycline injectable, and syringes with needles. LA200 is a known brand. Other than that, you can make sure the coop ventilation is good, prevent amonia odors or mold in the coop and run, and try to keep her drinking well. Feed stores love to sell VetRx, but it is just herbal oils mixed with camphor, and not going to treat a respiratory disease.