http://www.smartgroups.com/message/readmessage.cfm? gid=1423922&messageid=10136&startid=10141 In a 3 month old ferret I would wait till the spring time (end of Feb/beginning of March) to give the implant. They did give high doses of the implants to 8-10 week old mink kits without any side effects. No, 6 years old is not too old for the implants! Six is the age where there is a higher risk with surgery. Unfortunately there is no absorbable melatonin implant. Neo-Dynamics/Melatek looked into it, but they were not able to do it. I have not seen any problems with the "old" implants under the skin. Hope that helps, Jerry Murray, DVM [Posted in FML issue 4610]