He prefers straw - is this bad?

No matter how much fresh hay he gets i keep noticing him picking out bits of straw from the floor to eat, is this harmful?

does he still eat hay? if hes got golden poo's then hes getting enough hay in his diet but if his poo's are abit on the dark side i would maybe suggest stop using the straw and just use hay instead. i personally dont give my buns straw.

I only line the cage with straw, hes not meant to eat it! He is eating hay as well and his poos are a light brownish colour