Hi
@Matthew Maschona-Fortune
I'm sorry to hear you are having trouble.
What symptoms do your chickens have?
Any photos?
How old are they?
MG (Mycoplasma Gallisepticum) is not necessarily a death sentence. A lot depends on your chicken keeping goals. If you are trying to raise birds to sell, trade or show - then culling and starting over is may be better. If they are for your own personal use, then managing the illness and culling only those that are severely ill may be a the way to go.
http://edis.ifas.ufl.edu/ps044
http://www.merckvetmanual.com/poultry/mycoplasmosis/mycoplasma-gallisepticum-infection-in-poultry
MG is contagious and birds that have been sick, recovered or exposed are considered carriers of the illness. MG can be transmitted through the egg to chicks, as well as, from bird-to-bird contact, through dust, dander, housing on clothes, etc. This is why a lot of literature you see says to cull, this will help stop the spread of the illness.
Do some reading looking for "breeding for resistance in poultry" search here on BYC and google - this may give you information on how to weed out the weaker ones and breed only the stronger chickens - this can make your birds less symptomatic - they would still be carriers, but you would eventually (in theory) have fewer losses.
What do you use traditionally for infection (herbs)? We may be able to help you figure something out.
Do you happen to have any access to antibiotics - these can be used to help control symptoms (secondary infections). Tylan ( Tylosin), Denagard (Tiamulin) or possibly Tetracyclines?
Hopefully others will chime in - we will do our best to give you some suggestions. Keep them drinking. If they have discharge from the nostrils or eyes try to keep that cleared away. A sterile solution is best to wash the eyes - you can boil some salt water, let it cool then use that for washing out the eyes.
Keep us posted.