A good way to tell is when you REALLY LOOK INTO THEIR EYES.If you REALLY LOOK YOU WILL SEE THE SUFFERING AND PAIN and THEY DON'T LOOK LIKE THEIR NORMAL SELF ....like something is missing ! I can't believe this but I find myself crying for her as I type this to you. This pain I feel is like the worst thing in the world.One of the hardest decisions you'll EVER have to make is the decision to put a BELOVED PET to sleep but it is also THE MOST UNSELFISH one too.That is TOTAL UNCONDITIONAL LOVE to be able to hold your pet as the vets gentle hand does what I'm SURE SHE/HE HATES DOING !! That way your pet has nothing to fear because they are most comfortable and secure in their long-trusted,faithful companion"s arms and this is especially true if you have it done in your home. That way they are ALSO IN THEIR SAFE ATMOSPHERE NOT SHAKING FROM BEING PETRIFIED FROM GOING TO THE VET'S OFFICE! I think the cost is about the same as if you took them in.I'm sorry to say,but unless your dog has an illness it sounds like he is passing away.I recently had to put my 14 year old lab-mix down and I had the vet come to my home to put her to sleep because I DID NOT WANT HER TO SUFFER.Might I suggest you to look in the yellow pages for a house calling vet to come check him out and if he/she determines your boy is suffering,maybe you should euthanize at home too?Minnie was always so VERY SCARED to go to the vet.She would tremble and get REALLY NERVOUS,the poor baby! I didn't want her last hours on earth to be torturous to her,we loved her WAY TOO MUCH FOR THAT!!Dr Noble is the vet we had come to our home and she did so on an emergency basis so Minnie wouldn't have to suffer over the weekend.She was WONDERFUL and VERY HUMANE and CARING.She told me we called at exactly the right time because dogs,like people have a DEFINITE ODOR to them as they are dying.She told us that Minnie(our beautiful black beauty) was in the process of dying and as soon as she came into our home to put her to sleep she could smell it but it was not real strong yet.She told me we called it at a perfect time because one NEVER REALLY KNOWS WHEN IT IS TIME BECAUSE OF OUR SELFISH NEED TO KEEP THEM ALIVE HERE WITH US not being able to bear making the final decision and then to carry it out !! As death approaches closer,the odor gets stronger and stronger.She also told me the other dogs in our household (we have 2more) started pushing her away alienating her because they can REALLY SMELL death a lot more with their keen sense of smell and that is what animals naturally do.That made me so very sad for my Minnie.She was an angel and quite the gentle lady.Also as an animal senses death approaching they tend to hide or keep off to themselves.I asked Dr Noble why?I guess nobody knows for sure but one theory is they are actually scared of something for they feel death approaching but don't know exactly what they are scared of since,unlike us humans who know about death and know we all have to face it,dogs don't have a concept of it.Thank GOD for that,right?I would be a LOT SADDER if they knew. I'll pray for you guys and your BOY DOG AND LOVING COMPANION in hopes that all 3 of you will get through this as painlessly as possible !! GOD BLESS YOU !! Very Sincerely,Pam.