Welcome to BYC! Baytril from First State vet is way too expensive for me. Look here for less expensive Baytril:
https://www.backyardchickens.com/t/959119/baytril-enrofloxacin-sources
The Baytil doses I use most are:
10mg/kg twice a day orally or by injection
15mg/kg once a day by injection...