Both olive oil and molasses have caloric value and keep food in the gut soft.
You can use regular Prep H as often as you like, and keeping them hydrated is vital. Any photos?
I don't like the sound of that ripped tissue, is it possible one bird is pecking the other? ( in which case, they have to be separated too. )
Do you have any information from the provider of these chicks about whether there is a genetic problem? If you have been feeding starter crumble and water I don't know of any reason why you should be having this problem. Of course, others may...