I don't know if it helps, but the pictures of the chicken with the swollen, bubbly eye look just like ILT to me. In that case, you have to just keep them isolated, away from dust and treat with terramycin for any secondary infections and just hope for the best. You know, it occurs to me that your chickens are coming down with a variety of different illesses and this would indicate an underlying immunosuppresant event. Were your birds vaccinated for mareks. Sometimes they can come down with mareks and the mareks wont kill them or even be really symptomatic. What mareks does, though is that it really deftly supresses the immune system and leaves them open to all kinds of pathogens and, in addition (since you mention some birds with weak, shaky or deformed legs I believe), some pathogens can keep the body from absorbing certain essential vitamins and minerals. Coccidia, for example, can sometimes lead to rickets. Maybe you're looking at mareks as your cheif underlying cause, or maybe not, just a shot in the dark.