Hi, popping in to share my experience.
I have had Blue Laced Red Wyandottes and Blue Copper Marans, as well as a variety of blue barnyard mixes, not necessarily from those breeds. I have not experienced any health problems with this wide ranging group, and certainly nothing focused on blues in general. In general I would say my blues have been thrifty and vigorous. And pretty too.
To the point of the discussion above, none of them have been white layers.
Yep, the key is "white egg layers" but I've spoken with another breeder who said Blue's in dog breeding had issues. The issues with Blue chickens compounded by being a white egg layer with the genetic slow feathering issue might all be coincidental.
FYI - BYC is changing its format and may be "off-line" in a "read-only" format for a few days while in transition. Meanwhile, if BYCers are in withdrawal and still need to talk on-line BackyardHerds.com invited them to join for the few days while BYC is in transition. I probably will just wait until BYC is back in full swing and not bother with BYH. There's more info about the transition on the BYC thread BYC Software Conversion.