We have had good luck by applying Preparation H at the first signs of problems. The appearance of CTS is unpredictable and sporadic. Its occurrence is usually associated with offspring from particular pairs and can manifest in parent-raised chicks as well as incubator hatched ones. We have not found humidity to be a primary causal factor, though low humidity might aggravate the condition. CTS is often present in all chicks from a clutch while not effecting any from another, and it might occur at one time and not another with the same RH conditions.
Successful treatment relies upon early detection.
Prevention can be achieved by applying CitricidalTM Comfrey ointment to all toes from hatch through two weeks of age. Since it is not clear if CTS has a microbial cause, keep feet clean of fecal matter. The above ointment makes this much easier. F.B. was also one of the co-authors of the Complete Guide to The Eclectus Parrot. Quote from Harrison's newest heavy-heavyweight book.