French Molt (B.F.D.)

Budgie Fledgling Disease

This Article was published  in Budgie World Magazine. It has been re-written by Alan Bundy and certified as accurate by Steve Holland.

Budgie breeders have been dealing with a condition known as French Molt for quite some time. The disease, a virus more commonly known as Budgie Fledgling Disease or BFD is actually the Polyomavirus. It is recognized during the breeding season as the young chicks are about to leave the nest. Chicks can loose wing and tail feathers, and in severe cases loss of all feathers leaving only the down. The virus is know to appear from 8 to 30 days of age.

French Molt known as the Polyomavirus otherwise known as Budgerigar Fledging disease or BFD has been with the Budgerigar community for a long time. It is recognized early, as the fledglings are about to leave the nest. The BFD virus appears usually between 8 and 30 days, and can result in loosing a few feathers to in severe cases all of its feathers leaving only the down. German scientists Lehn and Muller isolated the actual virus BFD.  The virus attack was captured on film. The merge of the virus through the feather cell wall and the modification of the DNA were observed. Infected at this point the cell starts the onset of the active viral disease. White blood cells attack non-normal cells or the virus and attempt to kill it. White blood cells prevail and at this point generate antibodies, which prevent any further infraction to the virus of the budgie. In severe cases if white cells lose the fight, the budgie will die.

The Polyomavirus is attracted to hot spots on budgies, these hot spots are enriched with blood and nutrients where major growth areas begin. The long tail feathers are the hottest spots on a young budgie. The quill is inflamed by the attack of the virus and causes swelling. The blood supply is cut off by the white blood cells causing the quill to rupture at the feather shaft where the remaining blood begins to dry. At this point the swelling changes the shape of the feather shaft to a shorter blunt end.

Only budgie chicks experience this type of response to the BFD virus. Exposure appears between 8 and 30 days. It is possible for an adult bird to contract the virus however there appears to be no resulting damage. An adult can contract the virus however it does generate antibodies to the virus.

Additional strains of the BFD virus have been discovered in recent years in German labs that are significantly different from the initial BFD and are known as BFD1 and BFD2 etc. BFD1 causes death in many cases. This strain can mutate very easily and each Aviary can develop a slightly different strain of the virus as stated above. Each Aviary then establishes its own antibodies for the particular virus contracted. When the antibodies exist there will be no outbreaks of the BFD disease. This usually takes 2 years to resist.

Outbreaks can occur when a new bird with the BFD disease is introduced to the flock and can infect a new strain that then starts the infection/antibody process again. The result is a new set of antibodies that are reenacted again. 

In conclusion we have learned that BFD is an infant disease. It can be managed, providing new birds are not introduced into the Aviary while breeding. It is possible to breed BFD chicks which do not carry the virus but instead have developed an antibody to the disease. Each aviary has a different period in developing antibodies that can take approximately 2 years.