I live near the beach in Davao City, Philippines. At the local resort, Bago Beach (read that as a place to pay 20 pesos (50 cents) to get past the barbed wire fences), I walk my dog on the street outside. I watch these skinny guys climb coconut trees daily, harvesting the coconut water. They process it and hang it back in the trees in bamboo containers, where it ferments.
it is a favored drink for lots of folk, my wife' family included. I tried it. No thanks! I'll stick with red wine and Johnny Walker Red!
As for Balut, it is duck eggs, normally, not chickens!
Here is a link to a YouTube video showing the process of making Tuba (coconut wine)...

Yer’ right, it’s duck egg. My brother got married in Boracay to a great sis-in-law so I now have family in the RP. I miss everything from eating fishballs at the street sidewalks to someone waking me up so we can flag some dude who sells “taho” early in the morning (or afternoon US pacific time). and don’t get me started on Ginebra ans Red Horse..
Isn’t it a rotten Duck Egg?
That dude Zimmernman ate one on his show, and I thought I was going to puke on the dog.