Well, yes, if you're talking like white-dwarf star density. Although at that point the matter wouldn't really be identifiable as feathers. Really that's a sem

Well, yes, if you're talking like white-dwarf star density. Although at that point the matter wouldn't really be identifiable as feathers. Really that's a semantic question as to what is the degree of compression beyond which we wouldn't call it feathers. If you're compressing both, then no, the brick would compress more, since it's higher atomic mass per nucleus on average, minerals like silicon versus organic carbon-oxygen-hydrogen compounds.