Sick pullets

[welly]

Hello
I have 2 pullets that are 16 weeks old and have been fine until last night.One Cream legbar,Light Sussex.The CCl has a puffed up chest and is moping around still eating and drinking.The Light Sussex is kinda panting breathing fast.Please help us any thoughts and the light Sussex has a very pale comb compared to her sister.We have had chickens only 3 years and never had any health issues there coop is clean and water is clean.I looked around for any blood in the poo or out of the ordinary colors and don't see any signs of blood.
Thank you in advance.

 

[Chicka and Co]

I don't know for sure but maybe research sour crop (blockage in the crop causing bulge in the chest) or respiratory diseases in chickens. Maybe even worms although that would usually cause abnormal faeces. See if you can find worms in their poo.