This is just my opinion- I like the buff hen better.
I feel that putting a chick on the flyer would give people the impression that they would just be buying a cute little peep that would be small and easily cared for, as opposed to a baby chicken that will grow up to be, well, an adult chicken.
People already by chicks on a whim, especially during Easter, and once the chicks are grown, many are abandoned to fend for themselves, or dropped off at the humane society, which doesn't have the room or knowledge to care for them.
Please use the picture of the hen, so that people know that they are investing in a hen that will be useful for eggs, but still as cute and personable and a chick.
Thank you for listening to my little rant, and I hope your flyers are successful in dragging more people to the addicting world of chickens!