LOL. This must be the reason the Chicago Manual of Style indicates hyphens here. And it must also be the reason an MIT Press copyeditor reviewed the whole manuscript very carefully. (Which then triggered some legalistic arguments from me citing chapter and verse of said stye manual.)

For about five minutes I was trying to figure out why you were feeding your lunch. Some sort of creature perhaps? Then I realized you probably meant 8-month-old, as in baby...