The US culls 350 million male chicks per year, per this article. Wikipedia says billions of male chicks are culled worldwide, which seems plausible when accounting for EU, China, India, SA, SEA etc. The citation on Wikipedia looks legit to me as well.

Edit: Wikipedia does indeed cite several different figures, including a "billions" number which does not seem plausible. Thanks monster_truck for pointing this out, and apologies for my misunderstanding!

The Wikipedia article clearly has some errors, but I'm not sure where since I'm not an expert. In one spot, it says 7 billion chicks are culled annually worldwide, in other it says 8.5 billion just in the US. I assume these are likely estimates taken from different sources or at different time periods, but still, I wouldn't assume Wikipedia is accurate.

IIRC humanity eats like 70B chickens a year so sounds very plausible to me.

That kinda checks out. 1.2 billion hens are butchered in the US annually. So, maybe not multiple billions of male chicks in the grinder. But, certainly over a billion.

It might get to 2 billion if you count 375 million layers and some untold number of personal chickens.