You know, that's pretty much the same argument my one-time boss gave against children's fantasy books. I didn't think the argument was valid then, and I don't agree with it now.
The near-accusation is rude and unfounded.
It's a little harmless sparkle and a little paint. Pretty sure the OP's grandchildren know chicks don't come in purple naturally.
Neither is a coop. Or pelleted feed. Or anti-coccid medicine. Yes, it's a little ridiculous. The chicks themselves do not care.
To the OP. Yeah. They're not legal for sale in PA. And I rather see why, as I know a few people who used to get Easter Chicks.
Which does not mean that the technique itself will harm the chicks, only that some people are animal abusers. You don't deserve to be lumped in with those people, and I'm sorry this thread turned into such angry disapproval.