She is about 5 months old has not yet started to lay her eyes are normal not bluish grey like i have seen in some pictures, i will try to get some pictures in a little while, i feed her agway starter / grower and occationaly throw down cracked corn. I have had some other birds get sick most loosing balance falling over and turning head but in the past the duramycen has helped them i had one hen wigh leg paralysis but it started with only one leg for over a week then moved to the other i put her on tylan 200 and a vitamin supplement in the water called redcell, she got one leg back, i think the damage is permident to the other, but she gets around ok she seems healthy again. I think i had three birds sick this winter all between 3 and six months of age, but it has been a long tough winter.
The reason I asked for pics of the eyes isn't just for the coloring, although they can and do change color, it is also for the pupil. It will change shape some/most times, but then again, not always. Now....you saying that some of them would lose balance and turn their head, can you explain this more? I'm thinking this may not be Marek's, but please, don't get your hopes up yet. There are vitamin deficiencies that can cause very similar symptoms as Marek's, as well as a few others I can think of off the top of my head. Aflatoxin poisoning is one. Feed not having the proper nutritional value it's supposed to have, another. The vitamin supplementation along with the antibiotic, you gave, caused improvement, right? We're stepping into grey area here but just based on that, I would say it isn't Marek's. I don't have enough info and am guessing, but I haven't seen you mention any deaths yet either. Nor any wasting of their bodies.
My advice? I would go out and get them a different feed. Maybe a show bird or a game bird food. Mix this into what they already have if that's all you can do, if not change their feed entirely to a brand name one. Purina or one like that. Is the Agway feed Blue Seal? Another thing, how is the poop?
Marek's birds can get better, but will usually relapse and die.
Yeeeeee maybe, lol. A lot of times this is the case. There seem to be 3 markers in their lives, at least from my experience, the 6-8 week mark, the 6 month mark and then the 1 year mark. It's really a weird thing and it's just about like clock work. Mine that didn't die or have to be culled from the initial parallysis, most got better. The ones with the stumbling gait having the most improvement. The ones with full paralysis...I've had a couple come back from it only to later die at the 6 month mark. They are never going to look like the full sized chickens they are supposed to be either. It damages them inside, but again....this is strange as well. The females are stunted, no question. I have one Black Jersey Giant hen left. She is 1/3 the size she should be. Now I have White Jersey Giant roos that started stunted just like her but are now full size. Slight protruding of the keel bone, but still full sized. Weird huh? I'm wondering if it may be due to the different hormones. I lost a few of the roosters during the intial onset of the disease but by far many more hens. At the 6 month mark, again it was the females hit the worse with almost 100% mortality. [1 male to 6 females.] I'm coming up on the 1 year mark in May. We'll see.....