I don't see how anyone could possibly know what the subjective experience of being a day-old chick stuffed in a box would be like. But I can imagine what it would be like to be a human stuffed in a box, and that doesn't seem very pleasant. I don't see how the idea that it might be better for birds (who are pretty clearly sentient creatures) could be based on anything other than rationalization and wishful thinking.
I think the assumption that the fresh chicks just hatched from an egg (or in the case of a human came out a womb) wouldn’t be too panicked about confined spaces.
I think a more apt comparison is to imagine a human being shipped in a padded shipping container with a dozen of her friends to keep her warm and help her feel safe.
I've had chicks shipped to me this way and it didn't appear to be traumatic at all for them. They grew into happy, healthy birds.
