I too suspect it may be Marek's that you are dealing with. Losing coordination of their limbs/loss of balance/appearing drunk is a common symptom of it.
When you say you quarantine new birds, how recently did you introduce new birds after quarantine and what is your quarantine set up? Marek's can be carried on clothing, shoes, skin and hair as well as the wind. Where did you get the birds you introduced and how old were they? Have the new birds shown any symptoms or just your original flock?
Marek's birds can appear perfectly healthy for months, even years and then develop symptoms. Usually it is stress that triggers an outbreak. Stress can be integration into a new flock, moulting, surge of hormones at point of lay, harassment by a young cockerel etc. If it is Marek's, it sounds like you have a particularly virulent strain with it killing them so quickly. Marek's also suppresses the immune system, so they may be succumbing to coccidiosis as a result of that. It might be worth trying Corid treatment and then a good quality poultry supplement like Rooster Booster
When you say you quarantine new birds, how recently did you introduce new birds after quarantine and what is your quarantine set up? Marek's can be carried on clothing, shoes, skin and hair as well as the wind. Where did you get the birds you introduced and how old were they? Have the new birds shown any symptoms or just your original flock?
Marek's birds can appear perfectly healthy for months, even years and then develop symptoms. Usually it is stress that triggers an outbreak. Stress can be integration into a new flock, moulting, surge of hormones at point of lay, harassment by a young cockerel etc. If it is Marek's, it sounds like you have a particularly virulent strain with it killing them so quickly. Marek's also suppresses the immune system, so they may be succumbing to coccidiosis as a result of that. It might be worth trying Corid treatment and then a good quality poultry supplement like Rooster Booster
