Have you considered paratyphoid, or other problems? maybe probiotics (probios used to be cheap..).
Er.. yes, the two competition "breeds", are actually three types, or maybe classes(?)..
parlor rollers should never be left to roll on anything but soft surfaces as carpet. even. they easy can get injuries from rolling head over feet n tail, causing concussion, abrasions, broken wings, etc. breaking blood feathers are bad also. so odd most keep them in wood floored etc hard surfaced cages.
parlors are as proper performance bred bird, supposed to not roll for nothing, and are kept in low cages etc to do this mainly.
parlor rollers-are startled to roll continuously on/along ground (seen judging based on how connects with ground as rolls), on soft low level fields (astro terf etc. as well..), in straight as perfect as possible, lines, for as far as can, all at a time continuously. record being three and something football fields of four maybe (that much level open area apparently hard to come by).
Parlor rollers are raced as well..
General non competition parlors roll all over, on ground also, and are distinct in shape size, etc etc etc.. and are not mixes of flying rollers. I've kept all and very distinct from other rollers. rollers being general name of origin, but many breeds of roller do not, or only roll as good as a tumbler, and/or like a parlor tumbler even. though mixes happen al lot to put more roll etc into competition n non competition performance Birmingham rollers, and to try to put more/some roll back in show only rollers.
Parlor tumblers-that are actually two classes of now for competition.. that are on wood or astroterf etc, were the bottom of feet are marked, and then the bird started to perform either a single, or double, backflip, and are judged mainly on how close they landed to were they started at, on feet, being tight low off ground tumble. Other factors come into play maybe as well,being form/control and tightness of flip.
Regular parlor tumblers just jump/fly up three or four feet and tumble back down.
some bad birm rollers, and cross breeds of birms and parlors in general, also act like that, but again if seen parlors, they are distinctive.