I gave it to mine before youngbird racing, because i bought a couple of pigeons in and after a couple of weeks these showed signs of cancker, i gave emtryl, after a few days i thought i had para they were twisting upside down falling off perch's etc, i'm not one for medication normaly so never reliased that these side affects were from emtryl, the young birds that i kept are a picture of health now, but what does worry me if it's done any lasting damage, Regards