CX Meat Birds coughing and wheezing? What's wrong/Can we still eat?!

I have a group of CX meat birds that are supposed to be butchered on Saturday. Tuesday they started making weird sounds but I didn't think anything of it. I thought they were just getting their "big chicken clucks" and growing out of their cheeps. Now they are coughing and I lost two that started wheezing right before they died. There is no nasal or eye discharge and their poop is completely normal and so is their eating/drinking habits. Can I still eat them with this strange illness or should I not? They are averaging 8 pounds live weight and I cannot keep them any longer. The only thing I can think of is that their breast meat is constricting their airways.

 

If I butcher them tonight while they are still doing okay, can I still eat them and not worry? If it is heart failure, I don't see why the meat would be bad.

 

Yep they had the excess fluid. Butchered 20 tonight, will do 40 tomorrow and the last 40 on Saturday. Their lungs and all other organs looked extremely healthy.