Ashdoes, sorry to read of your trials, it's very difficult to deal with. It sounds as if they don't know whether it was Marek's yet, and I would think by now they would know that, but the Marek's discussion is useful.
I have read more papers on Marek's than I can even count. One frustrating thing is that it is transmitted via feather dust. I recently read (another keeper wrote this, I've not found a study that says it yet) that it remains in the soil, so you can move to a property where poultry previously lived and pick it up - that was news to me - and a third person said there was some evidence it was transferred from parent to chick through the egg, although that person was not able to support the claim with any evidence. That doesn't mean neither of those things is true, it means I haven't read it yet in a study, and this summer I have not had a whole lot of reading time.
Transmission by feather dust is really all I need to know - it means keeper down the road whose birds are carriers (and in theory, all adult birds are carriers, whether vaccinated or exposed and surviving - live vaccine means the birds shed the virus for life, and that's the only kind available) - anyway, keeper down the road goes into the feed store and brushes his/her carhart against the bag of food that's about to be loaded into my car. Guess what's on all our coats?
Most studies I've read say it is everywhere - there was a study published by the University of ... rats, New Hampshire? Vermont? Someplace in New England, that said if you have an adult flock of poultry, you have Marek's. Culling the entire flock and starting over is generally not thought to be an effective long-term solution - I know the CSU reps recommend it, but unless you subsequently have only vaccinated stock, it isn't going to cure the problem. Even if you can somehow eliminate any possibility of Marek's currently on your property, it's a matter of time before it comes back - and not because you do anything careless, but because if it is transmitted via feather dust, and carried by wild birds, I don't know how you can avoid it. That leaves vaccinating or raising a resistant flock.
The vaccine is available only in 1000 (or more) dose bottles. The entire bottle must be mixed all at once and administered within 2 hours of mixing to chicks in the first 48 hours of life. It *can* be given to older chicks, but the effectiveness decreases as the chick gets older. Each bottle is ~ $20 plus overnight shipping with ice packs, plus you need syringes and needles. The cost of vaccinating chicks when you are only hatching a couple dozen, give or take, at a time, adds about $4 per chick. For a higher priced chick that may not make a lot of difference, but for most of us it does. When the price of a chick goes from $4 to $8 (hatchery versus local breeder who vaccinates), most people buying chicks are not aware of how hatcheries work, and will happily buy the hatchery chicks. It isn't their fault, the information has to be sought, and people have to think to look for it.
The vaccine you and I can buy is commonly referred to as Turkey Marek's - turkeys carry it, and if you add a turkey to your flock, you organically vaccinate the chicks. This is what I have been trying to accomplish the last year, but I've yet to locate a small turkey to add to the flock. Keep in mind, though, this means when chickens and turkeys are kept together, all are carriers. The chickens will not get sick, as they have effectively been vaccinated, but just like a bird vaccinated with a needle, they will shed the virus for life.
Raising resistant flocks means dealing with losing some the first year, losing fewer and fewer each subsequent year as resistant stock is used for breeding and perpetuating the flock.
Lastly, I will share a story I've recently read of a keeper across the country from us. This family has a nice flock of chickens from which they have shipped eggs only to a few people, mainly to try a few different shipping methods and see how they work. Super nice, responsible, caring keepers with only the absolute best interest of their flock at heart. They learned of some hens that needed rescue, and their big and kind hearts could not say no. Luckily they were kept separate from the rest of the flock, save the addition of one of their males. One got sick, then another got sick, so they searched and found a way to test one that had died. It had MG - Mycoplasma Gallisepticum. All the rescue birds do. None of their original flock does. Unlike Marek's, MG is treatable - but like Marek's, survivors are carriers for life. If you talk to the folks at CSU they will tell you it's a fool's errand to cull the flock for MG because it is endemic. If you ask the GA State Vet, he will tell you to either cull your entire flock or keep the flock 100% closed forever. I find this confounding. Cull for one endemic disease and not the other here, not the same in GA - I don't know what that vet's position is on Marek's. The sick rescue hens are not in GA, by the way, but another flock where MG diagnosed was, a few months ago, and they destroyed a flock of something like 120 well-bred Orpingtons. I can't even imagine it.
Each of us has a unique environment in which our chickens live. Bringing in chicks or eggs from a different environment, no matter how carefully, is going to stress them, and create vulnerability where there may have been none before. I've lost birds to impacted crop, internal laying, recently talked to someone who lost one to kidney failure who had taken it to a vet, who did the necropsy for free because *she* wanted to know what killed it, as they had successfully treated similar symptoms a few months earlier. When she found kidney failure, she told the keeper nothing either of them could have done would have saved the bird. That is going to happen. We can put ourselves through torment trying to figure out how to save every single one, or we can follow the counsel of keepers who've had birds 50+ years, who tell us to raise resistant flocks, and stock the medicine cabinet with an axe. Or something in between. We should just remain mindful that sometimes chickens are going to die no matter how well we care for them. They have to live in the environment we have.
Pullets are hard to find this time of year.
