2 year old ball won't eat and seems very stressed.

They're just weaned rats, they're not very big. Plus he's not eating right now anyway...

Do you have a temp gun to check the temps or how are you judging them? I'd guess either too hot or stressed from the bird, is there a thermostat on your heat source? Is it an undertank heater?

I solved a similar problem in mine by effectively covering the whole floor of the viarium in cork bark with a fake plant stuck in the middle. Only uncovered area is stuffed with water bowls. After a settling in period mines eating again.

Try increasing the hides, totally empty and clean the vivarium to destroy any and all scent traces, then let them adust to it for a week or two. If you have the husbandry correct this probably will work. I figured that making it seem like a new rodent burrow to live in might help, after all if there's too much snake smell its going to make hunting harder.