I've been treating sneezy/congested/hoarse sounding chickens for the past week with Terramycin in their water. I think they get better, then I think they slide back and it's been a guessing game all week as to whether or not it's working. The package said to give for 7-14 days (7 days will be tomorrow) I want to move on to Tylan 50 injections. Should I wait a timeframe after Terramycin before that? Give it now? Stop the Terramycin or continue it?