Yes, you'd want to have the chicks picked up and expressed. I'm sure the seller won't mind so long as she's not held liable so if the chicks are able to be picked up and then mailed in a timely fashion it should be fine. I've mailed started birds and adults many years ago without any issues. I had some bantam Black Sumatra shipped from Florida to Texas and the post office was super amused because the box was shaking around like the opening scene of Jurassic Park and I had to explain they were eating their apple.