I just goolgled in Parrot spasms feet and it came up with this?
Under accute especially it does mention the spasms with the feet, and its linked to symptoms like you mentioned with his feathers.
Pathogenesis of PBFD
The incubation period and clinical signs produced by this virus are very variable, depending on the infective dose (amount of virus infecting the bird), and the age of the parrot and the stage of feather development at the time of infection. As the immune system develops, birds become more resistant to infection, and the signs less severe. In general, birds over 3 years old are rarely susceptible, but cases can and do occur in older birds if heavily challenged, or maybe latent carriers become clinical following an episode of stress. In juvenile (especially hand reared) birds with an undeveloped immune system, the incubation period between infection and development of disease may be as short as 14-28 days, and illness will be severe. In older birds, incubation can be many months, and clinical signs are insidious and chronic. The course of the disease is very variable and carrier birds shedding the virus are common. It is therefore difficult to eliminate the virus from an infected population, and many collections of birds are positive.
Disease patterns may be described as:
Peracute – sudden death with no previous signs of illness in newly hatched chicks, most commonly cockatoos and African grey parrots.
Acute – mostly in nestlings or very young birds during their first phase of feather growth. There is usually a loss of powder down, with resulting shiny black beak in those birds whose beaks are usually dusty grey. There may be abnormally coloured feathers (e.g white in the normally black Vasa parrot, pink in the African Grey). Affected birds become quiet and depressed, and with a generally ‘grubby’ appearance. Many have diarrhoea, and all will succumb quickly to secondary infections. The classic manifestation of this type of PBFD is the young, recently purchased African grey parrot, showing depression, abdominal pain, bunching spasms of the legs and feet, with a post-mortem examination revealing Aspergillosis infection. This fungal invader is a common secondary problem in such an immuno-compromised bird.
Chronic – the classic form of the disease, found in older birds, with feather loss and deformity increasing with each moulting cycle. Beak and claws become brittle, necrotic, and deformed. Feather loss will eventually affect the whole body, including the head, whereas plucking parrots will have normal head feathers. This disease is invariably fatal, but individual may survive for many years if allowed to, and supported by their owners.
Carrier state – birds showing no clinical signs of the disease, but actively infected and shedding the virus to infect other birds. Usually mature birds, and commonly budgerigars, cockatoos and cockatiels.
For the full site details
Psittacine Beak and Feather Disease (PBFD), veterinary advice and assistance for the parrot species