I don't believe you can daisy chain floppy drives on the Mac. Like the eject button, the daisy chain port was included for the Apple II line. At one point Apple wanted a universal floppy drive that would work on both a Mac and an Apple II. Apple likely could have made the daisy chain port work on the Mac but by the time the daisy chainable drives came out, Macs were moving to hard drives so there wasn't a real reason to modify the Mac ROMs