rat poison case?

Question
Hi, this is not in relation to a pet rat but is about a young wild sick rat I found one week ago. I suspected rat poison but I can't seem to find very good info on the symptoms. He was very cold, weak shaky and thin.  at first I didn't put him on heat and I went out and came back and he was almost dead but revived with hottie.  Over the past week I have fed him up, keeping him in the hot water cupboard in an aquarium.  he no longer seems to need a hottie and escapes from time to time into the cupboard.  however his tail is partly dying which I think happened when he got so cold, frost bite and maybe anticoagulant combined? at first he could only drink milk, not eat, now has good appetite.  however despite all this I don't know if he might still be slowly dying from rat poison or if even he had some other disease.  he is sparse of fur on is face and his coat is fairly thin all over.  he has put on weight.  and in any case if he does pull through I am not sure where I can safely release him....been racking my brains over that.  I am not keen on the idea of captive wild animals - I think he is getting sick of captivity. my main question though really is what do you know about the effects of poison and is it likely he was poisoned?  If so, is it likely that I am just prolonging his death? thanks, Beret (new Zealand)

Answer
I'm sorry I took so long to respond...I had to get a little help on this one.  I sure hope the poor baby is still with you and hangin in there.  

Please take a look at this link.  Hair loss is one of the symptoms of poisoning but it's possible he was ill which also could be a cause and you might have helped him over that.  Time will tell.  It does take some days for poison to come into full effect so I advise you to continue to watch him for a few more days.  If he survives past a few more days yet still shows illness, I hope that you would be willing to treat him with amoxicillin for infection which he may have.  That would be treating him for at least 14 days.  If you release an ill rat into the wild, he will be doomed not to survive.  You can buy amoxicillin cheaply on the internet or at a local fish supply store (possibly).  If you need help with dosage, let me know and I can research that for you.  I hope he will be better and survive!

Here is that link --> http://firstaid.about.com/od/poisons/qt/07_rat_poison.htm