Though I didn't know "Slurp chicken soup, when catching a cold" is grandmotherly wisdom, it reminds me of the experience that I recovered from sick after eating chicken.
The first time I knew that is when I visited Busan via Fukuoka in 2010. When I was in hot spring, I felt like catching a cold. But, soon after eating chicken giblets, my health got better.
The second time was during a trip to Malaysia in 2014. While I was walking in high humidity and high temperature, I got runny nose and subtle pain in stomach.
Then, I went to Korean restaurant, and ate Samgye-tang, which is chicken soup with rice and some kinds of seasonings.
It made me fine just 30 mins later.
There is the third time, but I'd like to omit explanation, because it's similar to the first one.