Rooster vomiting

[The_Chicken_Tender]

We have a young Crevecoeur rooster, and about two day ago I saw him open his beak and a milky white substance came out. Right after that, he was eating and walking around like nothing happened. Today I saw it happen again, but he still seems to be acting completely normal. He is also a Marek's survivor (we are pretty sure it was Marek's), and I don't know if that is related or not.
Additionally, a couple weeks ago during a brutal heat wave, we brought all of our chickens in the house. During that time, our Polish did the very same thing. We kept her isolated for a few days, and it never happened again, and she is completely fine now. I wonder if this could be heat related, as it has been pretty warm for the last few days (nothing close to what it was during the heat wave though).
Any thoughts would be appreciated!

 

[Eggcessive]

I would feel of his crop in the evening to see if it is full and puffy or hard, and then again first thing in the morning before he eats or drinks, to make sure that it has emptied overnight.

 

[The_Chicken_Tender]

T

I would feel of his crop in the evening to see if it is full and puffy or hard, and then again first thing in the morning before he eats or drinks, to make sure that it has emptied overnight.

Thanks, I will do that. If it hasn't emptied overnight, what could that mean? Would that indicate sour or impacted crop or something?