Wow- you did this all yourself- I can't tell you how truly impressed I am. I could not do that alone. Hard work and also hard emotionally. Hugs. I know I would be crying my eyes out. We raise they guys from chicks, see them grow, develop personalities, and grow attachments- heartbreaking when the time comes.
Last time, we processed 15 large cockerels and a few adult RIR at one time... by plucking by the 5th cockerel, I was so exhausted holding all that weight suspended messed up my shoulder for a few weeks afterward. Plucking chickens is a tough job!
We now use one of those auto pluckers with the fingers. They work really, really well, and save wear on your body. Just make sure the chickens to be processed are not little/ tender skinned, or it will tear apart the skin, and tear the wings off. (Even if you put in many tiny little ones in, it is still rough on them.)