Why do rollers ... roll ? The truth

[Hambone]

What causes Birmingham Rollers and tumbling breeds to roll and tumble ? I read several articles via Internet about the subject , some say its a siezure and a genetic defect in the birds , others say its a trait just as some hunting dogs are pointers and setters and just do what they are bred to do .

I fail to see how it could be a random siezure because they can all do the roll together after lots of flight hours and training . I suppose its possible , but it doesnt make sense to me how they would all do it together UNLESS one bird had a siezure and the others just imitated its actions , then another bird siezed up and was imitated ? Hmm , now I'm thinking too much

Maybe the birds just learned to get a kick out of doing backflips ? LOL .

Those of you that fly these fun birds , whats your take on it ?

Hambone