at what stage do hairs start to turn red?

im 4 weeks into flowering and some of the hairs are starting to turn red.... about 20 % on the top couple of buds........ they still have not filled out yet but the hairs are turning red,

when do the hairs usually start to turn red? before the calyxes develop or after?

im growing skunk #1 and highgrade !

im sure alot of that depends upon the genetics of the plant. i just grew some bubba kush and thier flowers started out white but about a month into flowering they all started turing a dark rusty orange.
but some strains will start turning color in the last couple weeks before harvest.