[grumpydad]

most vaccines are administered via the chicks water supply, from 1 day old for mareks, through a range of various vaccines covering a wide spectrum of diseases.

this will then rely on the chicks drinking enough after it has been administered, and it assumes that it has been correctly dosed, and that the vaccine is still active.

this is not always the case.

part of the problem with mareks, is that there are various strains of the herpes virus that can affect the chickens, and like most of our human virus strains i am sure some can mutate. mareks can also remain in a bird without developing until it is triggered, usually by stress, the stress affects the birds immune system, the mareks then breaks out and the bird is unable to recover, we have been through this 8 times, always with the same result.

we also gave the birds the best chance we could, tylan, baytril, septrin, etc all to no avail.

the only bird that we have left from our initial batch is big sal, a large blue laced wyandotte. we know that she could be a carrier and were advised quite rightly by other members here to cull her, but at the time she was laying, and i was unable to cull an apparently healthy bird, which is why we decided to have some hybrids, hoping that being cross bred, they may have a stronger resistance to disease, and also we knew that as a commercial bird they would have been vaccinated.

this is a gamble, we know that, but so far so good, only time will tell if we did the right thing.

we also know that if they birds become ill, they will all go for at least a year to clear the ground, at which point we will have to decide if we will restock.

but at the moment they are all laying, so as only a happy healthy hens lays eggs, we are not complaining.

[jhub]

Thanks GD-useful info
Jane