No need to quarantine, I don't think, other than to maybe limit his movement.the others dont really pick on him. he’s had that bald spot since day one. it dosnt seem like a cyst to me it looks like its the top of his thigh and only juts out when i hold the chicken and his legs push in. and he has a great appetite. did u notice how the foot is splayed out a bit? his wing also appears to be a little limp; i cant tell if he’s using it for balance or cant really control it. Is there anything i should be doing to help him recover? should i keep him in quarantine ?
And the leg thing didn't happen until after you put the perches in? A splayed leg could be a deformity, but it doesn't look all that bad to me. The wing is probably compensating for balance.
My Polish frizzle, Twiggy, has a much much much worse deformity. Her leg splays out at about a 90° angle. But she had hers since hatch (or shortly thereafter). She manages fine, but I won't be keeping her with the big flock because I don't want my roosters mounting her. But here's a recent photo. You can see her wonky right leg:
She hops, and her right wing droops because of her inability to balance well. But she's growing fine and loves chasing bugs. My vet recommended that I euthanize her. I'm glad I didn't! She has a fine quality of life. If, at some point, she deteriorates, then I'll consider that, as well as other options. But it seems wasteful to kill her if she's not in pain or miserable.