I am not sure what the difference is in culling a chick that you know you do not have the space, time, or use for, and culling the same chick after feeding him up for 20 weeks to eating size. Most roosters are culled at some point, as there is simply not enough room for all those roosters. And anyone who has bought sexed pullet chicks is basically culling, as the extra male chicks - basically a by-product - are killed immediately at the hatchery. Re-homing simply means for most roosters that they will be eaten, just not by you - and that you have no control over how they are treated once they leave your ownership.
If you have the time and resources to take care of chicks with debilitating abnormalities, good for you. If not, kinder to kill them immediately rather than letting them linger.
This is an excellent point. If you have a flock that is more hens than roosters then you participate in culling whether you do it yourself or not. Healthy birds died or were otherwise held from the population so your flock can look like that. This is for the overall well being of all of the birds.
What is the definition of only culling for deformity? An appearance flaw is inherently included in that definition as it is a genetic deformity. Any domestic chicken that you have exists because of generations and generations of this practice.
http://www.merriam-webster.com/dictionary/deformity
Irresponsible breeding has long term consequences that are not good for domesticated animals overall.
That's exactly what I was trying to say.