So...... My guinea pigs spend at least 6-7 hours outside eating grass all day, they are brought in at night, well at 5pm , and a lit bit later in daylight savings, anyhow, if they have been out eating grass all this time do they even need hay, say lucerene which is kind of minced up? I do give them a dish of goats mix which has heaps of roughage in it for them, I have straw bedding on top of newspapers for inside, at night and in their day house, which they do Munch as well,and of course their veggies...