Unfortunately a simple dropping and throat swab isnt enough, in my opinion you will need a dropping culture made, to find out what is exactly wrong and the most effective treatment against it. Droppings and swabs do not offer the full picture what a culture can. But in my opinion you have been misguided if they've told you they have young bird sickness, and to treat with Baytril, to me it suggest they fear much worse, then can be shown in the basic dropping and swab test, "But hey, Baytril is an all round antibiotic so it should treat it" is the feeling I'm getting from what you have stated they have said. However I wish you can pull them through and best of luck for the coming season.