Possibly Egg-bound?

[farmerbrowne]

Ok so its not a bacteria that you cpuld vuew per se

 

[Eggcessive]

Mareks disease is caused by a virus, not a bacteria. It can be obvious sometimes when tumors are seen on the organs. They usually do the PCR testing as well. This link has clinical signs and gross lesions if you select Mareks disease under “view all diseases” and then click on gross lesions or clinical signs for good pictures of what can be seen on necropsy:
https://partnersah.vet.cornell.edu/avian-atlas/#/disease/Marek's_Disease