A third thing to consider is necrotic enteritis, which I think is quite common in Pakistan and would explain the sudden deaths. Treatment for that in the US would be something like tylosin.
If I were in your shoes and unable to have a necropsy done I would think about treating for coccidiosis...
I am very sorry for your losses. :hugs can you contact the university and talk to someone there? Maybe they can help you arrange to have a necropsy (animal autopsy) done.
http://www.uvas.edu.pk/facility/u-d-l/index.htm