The truest words ever spoken about dog ownership were by Warren Grimsby of Warcon Kennels. He used to say "Whenever someone offers you a lot of money for a dog, take it because you're only a single heart beat away from nothing".
A client had a mediocre dog (we had to qualifying wins on her but I knew she'd never be an Open dog) and a lady offered him $10,000.00 for her. I told him to sell, he didn't. About three weeks later he found her dead in her kennel, killed by a brown recluse spider.
I had a great youngster of my own I was bringing along. He was a year and a half and finished every derby and qualifying he ran, never winning, only jamming or placing. I loved him. He was a Honcho pup, huge, smart as his dad, and a character. I was at a trial in Billings, Mt. and he jammed a derby and qual. A person came up to me and offered me $8,000.00. I told him to double it and I'd think about it. He wouldn't go that high so I took him home. Two weeks later he started limping on a hind leg. I took him to the vet and he was riddled with cancer. The dog was put to sleep and died in my arms. I buried him on the face of a mountain overlooking our kennel. Only a heartbeat away from nothing.
I personally have mixed emotions on this. If you don't have a lot of money, and someone offers you enough money that it could change your life, you probably have an obligation to your family to sell that dog. You can always train another one, maybe not as good, but functional.
If the money would not make a huge difference in your life, I wouldn't sell. Nobody could buy the dog I have now. At my age, she may be my last dog and it's worth it to me to keep her. I think of the great dog's I've sold, anywhere from $7000.00 to $15,000.00 and at the time I needed the money and any dog I had was for sale. There are nights that I lay in bed, remembering those dogs, remembering what and how much they gave for me, and I think that if there is a Hell, I'm living in it now.
So once again I find myself very much at odds with Doc; these dogs, they become a living, breathing, part of us and selling one is like tearing a small piece of your soul away. It is nearly as painful as losing a loved one, because really, you are. I've lost enough loved ones in my life.
I hate seeing a game bird die of natural causes, unless I naturally cause it.