I have 55 6-week-old hatchery chicks that have been living outdoors for most of their lives. It's so hot here in South Florida there's no need for heat lamps after the first week or so! They were recently moved to a new pen that has been used by other chickens. The weather here is extremely hot & humid. Today I noticed that some of them are sneezing & sound a bit congested. Otherwise they seem to be fine, as active as ever, eating & drinking as usual. I got some vitamin/electrolyte powder to add to their water, to boost their health. I also got the only kind of powdered antibiotic the feed store had, called TetroxyHCA-280. It contains Oxytetracycline HCI. The package says it can be used for control of CRD in chickens. Do you think this would be helpful for my chicks? If so, how much should I add to a 1-gallon waterer, and how long should I use it? I also got some Vet Rx. I have closed the door of their house & plan to pick them up one by one tonight and give each a drop of Vet Rx under each wing & on their comb. Does that sound beneficial? Thank you so much for any help & advice you can give me for my chickies.