Now in all seriousness, that design in Aart's post above is what I used when I lost the two chicks. They crawled under the block being held up with the screws got stuck and died. If you use it I suggest you cut "shims" and drill holes in them for the screws to pass through. When you raise and lower it put the shims under the block so the chicks cannot get stuck under it.
I know it is a rare thing, but it happened to me. I can also tell you it will be the chicks you want to live the most that will die, (Murphy's law will apply!)