Be concerned about MG - mycoplasma gallisepticum, a slow moving but contagious respiratory disease in poultry. I believe finches carry it. Our flock are carriers most likely since we had one tested positive, (we culled the 3 that were ill). No more signs, but it lives in the poop on the ground for up to a month in dry weather, and on clothing, hair, feathers, etc. The only way to get rid of it totally is to cull the whole flock, disinfect, wait 30 days and begin again. Not as bad as Mareks though, which will not die off in your environment. Good luck