Culling is the most difficult part of being a breeder, but it also might be the most important part. My personal choice of raising only heavy breeds makes this a bit easier, since they are all useful to my family and extended family for meat. The only time I have to kill baby chicks is when they fail to thrive or have a defect such as spraddle legs, but lucky for me this is now a rare event. I think I’m now reaping the rewards of having done what needed to be done over the years to get to this point.
I think Bob, Mel and others like Blue Hill Farm have made an important point about the risks of selling culls, and I ran into something similar. I always figured it was good practice to sell culled hens for a lower price for people to use as layers. It seems like a good outcome for the hens, and a good deal for people wanting young, useful hens. But now I’ve found I have to be more careful doing this. Even though I made it clear they were NOT for breeding and pointed out the faults, some of these chickens made their way into a breeding program. And then I heard from the unlucky person who bought hatching eggs from that mating. This person was not happy with the chicks she hatched from “my line”.
Starting this year I am only hatching the number of chicks I have room to raise myself. I prefer not to sell chicks so that I can see for myself how they mature and then make the call on whether they will live to pass along their genes. Any chickens that I don't believe should be used for breeding I will butcher myself, or keep in my own layer pen, or let them go to someone I know who won’t be breeding them indiscriminately. Another option is to sell to urban chicken keepers who do not keep roosters.
I know we've strayed a bit from the original question of culling for deformities, but I think this is a good topic. There is no question in my mind that any chicks that hatch with deformities need to be swiftly put down. The difficult question is what do we do with the rest that are healthy, but don't quite make the grade for breeding?