Turkeys might need Tylan 200, which is 200 mg per ml versus Tylan 50 which is 50 mg per ml. It makes less volume. You can give it orally to birds, which can prevent the muscle damage sometimes seen with injections. 10 mg per pound about 3 times a day for 5 days is about right.
Mycoplasma (MG, CRD) in turkeys can turn sinus infections, or into air saculitis from E.coli. E.coli usually requires sulfa antibiotics or other ones. Once air sacculitis occurs, it might be hard to get them to recover. If the Tylan does not help, I would ask a vet about sulfadimethoxine. Here is some reading about MG (scroll down for MG in turkeys
https://www.merckvetmanual.com/poultry/mycoplasmosis/mycoplasma-gallisepticum-infection-in-poultry
Mycoplasma (MG, CRD) in turkeys can turn sinus infections, or into air saculitis from E.coli. E.coli usually requires sulfa antibiotics or other ones. Once air sacculitis occurs, it might be hard to get them to recover. If the Tylan does not help, I would ask a vet about sulfadimethoxine. Here is some reading about MG (scroll down for MG in turkeys

https://www.merckvetmanual.com/poultry/mycoplasmosis/mycoplasma-gallisepticum-infection-in-poultry