Hi, I'm new to chicken raising and need some help..... My flock of 6 has been sneezing for a few weeks.... One started then the others... The only other symptom I could see were a few of them sounded horse... No swelling around face, no runny noses, no eye crust..... I decided to go with Tylan 50 injectables... So I've done that for 3 days.... They're coloring around their face is turning red, like its suppose too.... It's been pale and dry looking....it was cold and rainy yesterday so I put heat lamp in last night... I went out there this morning and 1 is still sneezing.... Should I continue the Tylan50 for 2 more days? They all seem to be underweight... Except my BR .. They are about 9 wks and 7 wks. I'm feeding Nutrena Medicated...but switched to non medicated while on antibotic.... They are all active...