My two birds are doing well otherwise, behaving normally, eating well, etc. but sneeze occasionally, have a little upper respiratory discharge (clear) and their poops are a little watery and off color (more dark than usual). At first, the diarrhea was attributed to giving them too much spinach but it has remained off-color. I gave them a bit of yogurt this morning to see if that would help. Assuming that this is just a run-of-the-mill upper respiratory infection, what's the best treatment? I've read at an online livestock supply store that Terramycin is not to be used in birds whose eggs are for human consumption. Is this true? Thanks in advance!