Yellow liquid running from chicks mouth and nose

[madison057]

I have a flock of 40 chicks that are about 2 months old. This morning I went outside to check on their feed and water to find one of my chicks barely alive. When I picked it up A LOT of yellowish liquid started draining out of it’s mouth. What is this? And should I be concerned for the rest of my flock?

 

[Aapomp831]

Does it stink like holy hell? It may be sour crop