In my opinion, the most humane and loving thing you can do for roosters is to kill them quickly and put them into your own freezer. When you sell a chicken, the bird is simply taking its chances. It might go to a good home, it might be eaten, it might be thrown out in the mud to starve, it might be used to train pitbulls to kill. Once it leaves your hands, you no longer have any controll over what happens to it.
This is said with kindness. It is not said to be mean. Anyone who can not deal with the reality of what happens to all the roosters, really should not be breeding any chicks at all. No hatching, no buying straight run, not even buying "pullet" chicks, because sometimes those contain roosters. The only way to not have to deal with roosters not being treated as loved pets (and only a microscopic number are ever treated as pets) is to only purchase point of lay hens and either not keep a rooster at all, or never allow the hens to go broody.
To tell yourself that roosters sent through the auction are going to go to loving perfect homes is unrealistic. It's like the people who abandon their dogs in the country because "a nice farmer will give them a wonderful home on a farm." Or the people who think that the cat they turn into the Humane Society will get a good home. Those people are lying to themselves.