So is 1/2 thicker than 1/4? Or does it depend on the gauge? I don't know the difference between different types of hardware fabric - I just buy the 25ft rolls of 1/2in at Lowes.
Sorry about your chicks…
1/2” hardware is the largest opening you want to have for chicks (and for big hens, too, if you really want to keep them safe. Otherwise, when they are full grown, you could use 1” welded wire (or maybe it’s 2”, can’t remember).