You 'n I have kicked this around a bit, and I do understand why you'd be on the fence about the whole issue ... it's easy enough for folks to suggest goin' through this disease, 'til they actually have: It's no fun. At all.
But, neither is the thought of startin' over from scratch; the 'undoing' of all you've done so far.
But, most folks don't realize that it's so ridiculously common in poultry that it really can't be avoided by even the most careful measures of biosecurity ... sorta like humans hopin' to avoid the flu, except that (at least so far) we're not likely to be infected by wild birds.
My birds are not inoculated, which I sorta regret. But, until this newest vaccine has been licensed, and is available? Nothing I buy will be, either. However, keepin' those that seem to just be limpin' along is problematic in so many ways: Those showing significant symptoms should be culled, whether you're hopin' to develop resistance w/in your flock, or not.
Speaking of which? Here's a [
broken link; see below]
focused google search, for that. You also might wanna google
Visceral Leukosis, which is the disease that Marek's actually is.
Marek's has multiple forms (some say four, but there's six herpes viruses responsible), and all infected birds are carriers for life. It's one of the most common lymphoproliferative diseases, but there are others that you'd have to differentiate their symptoms from ... easier said than done.
So is breeding for resistance, 'cause you may have only one strain, or even several, or even none at all, and what happens when the next arrives? Short of intentionally infecting all birds w/ all known threats, there's little hope of actually developing the 'super flock' I'd once imagined I could. But, 'til then? There's always replacements, and they're still cheaper than one dozen of even lousy eggs.
But, for those hopin' to try their hand at it, or just to definitively know 'yes/no' w/o necropsy? They can test frozen/shipped feathers by real time PCR. While googling it, I found yet another remarkably qualified lady at
NCSU's College of Veterinary Medicine, Dr. Isabel M. Gimeno. and this page about her serves well to explain exactly what the MDV is.
SoOo ... it actually turns out that those wild birds flyin' about are nearly as big of a threat to our flocks as the raptors are (but I guess I'll keep on feedin' them, too ~'-)
:: edit to correct broken link:
Go to
http://www.google.com, and
copy/paste the following:
"marek's+disease"+poultry+breeding+resistance+site:.edu