Do flaked grains absorb more liquid?

I have missed my post-mash volumes by a bit in the last couple of brews and today I realized that they both had a substantial amount of flaked oats in them: one was a NEIPA and one a stout. Do the flaked oats absorb more liquid per pound than crushed malt?

--GF

In my experience, flaked grains (wheat, oats, rye) swell and are gummy when mashed.  This leads to some increase in water retention in the grains.  For most recipes containing flaked wheat, rye, or oats, this has not been an issue since the amount is generally less than 10% of the grist.  Oatmeal stouts, NEIPAs and Rye IPAs are another matter.  I've generally added about 2% more water to the mash in these cases and usually end up with just a bit more wort than normal.

I have not seen the same issue with flaked barley.