Flaked Rye skips malting entirely, the same relationship rye malt has to it that flaked wheat has to malted wheat — raw rye steamed and rolled to gelatinise its starch mechanically, mashing in directly without a separate cereal cook. What it doesn't skip is rye's real handling risk: the beta-glucan (pentosan) content responsible for rye malt's notorious gummy-mash tendency is still fully present in the unmalted grain, arguably more so since nothing about malting has broken any of it down.
Rice hulls are just as necessary with a meaningful Flaked Rye addition as they are with rye malt, stirred in at dough-in to rebuild the physical filter bed rye's poor husk structure doesn't provide on its own. At 1.5-3 °Lovibond, its colour contribution stays modest even at a real percentage of the grist, and carrying zero diastatic power of its own, it depends entirely on the base malt's enzyme margin to convert — a real consideration at its 20% ceiling, since that's meaningfully more unconverted starch riding on the base malt's enzymes than an equivalent percentage of self-converting rye malt would be. Rye IPA and rye pale ale recipes sometimes use Flaked Rye specifically for its spice contribution without rye malt's own bready malt character layered on top. Rye malt itself is the natural substitute wherever Flaked Rye isn't stocked, trading a slightly different flavour balance for rye malt's own diastatic power.