Our 5 yr old OE Game hen became paralized in
one leg today. Our neighbor, a vet, diagnosed her
as having Marek's. He said that the others hens
are not at risk. From what I read on the net, I'm not
so sure. I should cull the sick hen immediately and
do what I can to disinfect the coop... or could she
be the only one affected?

Taken from "The Chicken Health Handbook" by Gail Damerow.
Pg. 126 -Marek's disease, caused by six different herpesviruses that primarily affect the nerves of growing birds.
Pg. 287 -Transmission -contagious; contact with carrier or infected birds or their feathers; contact with contaminated litter; inhaled contaminated dust or dander; spread by darkling beetle or lesser mealworm ( Alphitobius diaperinus ) found in litter; not transmitted through hatching eggs or on their shells.
Prevention breed for resistance (some chickens carry a resistance factor, "B21," detected through blood testing); practice good sanitation; provide good ventilation; brood chicks away from adult birds until 5 months of age (by which time they develop resistance); keep turkeys with chickens (turkeys carry a related though harmless virus that keeps Marek's virus from causing tumors); inject vaccine under skin lifted at nape of neck of newly hatched chicks, one-time vaccination confers lifetime immunity; do not expose vaccinated chicks to infection until immunity develops within 7 days; not all vaccines are effective against all six strains of Marek's virus.
Treatment -none, cull affected birds (unless you're breeding for resistance); some tumors, particularly those of the feather follicles, clear up and the bird recovers on it's own, but survivors are carriers.

That's very interesting. I used to have problems with Mareks back in the '80's but after I started raising turkeys afew years back, I haven't had it since. Maybe this will encourage people to raise turkeys ( which, unfortunately, are susceptible to Blackhead).

THANKS YOU SO MUCH FOR THE DETAILED
INFO!~SO QUICKLY TOO!

I was preparing myself to find her dead this
morning and she was the first one out of the coop
and actually is keeping up with the others walking
in the yard. Her leg is working, but she is just a bit
weak on that side.

Is this just hopeful thinking that she's better or can
chickens have strokes?

Should I isolate her from the others or just let her
be a chicken?

If it is Marek's, how the heck did she get it... there
are no other poultry around us?

I heard crows can carry Mareks, so there. I don't think you can prevent wild life from living off your chicken feed. ;)) I sure can't, so it is inevitable that something like this would happen.

BigBoy, I have heard about the desease and read a little about it but what is a black head and what do I need to know about it? Can humans get infected from eating black head victims? What breed of turkeys can naturally breed and still be a good bird for eating (size and feed conversion wise).

Marek's disease can be spread by so many different things.
Bugs, dirt, dust, droppings.
Say, for example, that you walked somewhere there was infected droppings, then walked into your coop, it could be spread that way.
I highly recommend buying The Chicken Health Handbook by Gail Damerow.
ISBN 0-88266-611-8 .
When I bought it last year, it was $19.95 US.
You can also get it through www.amazon.com.

Pg. 97 Chart 6-1
Protozoan Diseases
=Genera
Histomonas
=Disease
Blackhead
=Affects
ceca and liver
=Prevalence
very rare
(infectious enterohepatitis)
Pg. 250
Blackhead
Resembles -cecal coccidiosis, salmonellosis
Cause - Histomonas meleagridis protozoan present wherever poultry occur except where soil is dry, loose, and sandy; free-living forms do not live long, but may survive for years in cecal worm eggs; tends to affect turkeys more often than chickens.
Transmission - eating droppings from infected chickens, earthworms containing infective cecal worm eggs, or protozoa attached to flies, sowbugs, grasshoppers, or crickets; carried by cecal worms (Heterakis gallinarum); spread by wild birds.
Human Health Risk - none known