The way I'd approach this question is like this: "Are they laying eggs, walking around, clucking, acting like chickens?" <- if that answer to that is "yes" then continue.
In my own experience, only feeding mine fodder wasn't successful, (they stopped laying started moulting, etc) BUT, they had been raised on traditional layer feed/mash, so I use it as a supplement.
If you're having no such problems, then continue.
IMO, <- (OPINION ONLY!!!) feeding layer mash is really just convenient and something that big ag got over on us.
;-)
Don't get me wrong, layer mash works fine, but it's not a necessity, that's what I'm saying.
Lots of people all over the world feed chickens all kinds of things, and they do fine.
Go with what works for you!
Also, I'm going to back to feeding fodder only as of the first week of October.
I read that the drop in laying/moulting/etc. is only temporary, and that I should have just given them more time...
But again, whatever works!
Hope that didn't come off too snarky...
Cheers.
-KS