1. Piggy tells Ralph to blow the conch.
2. Piggy wants his glasses because he said he's blind, and that they need it to make a fire for a ship.
3. Ralph wants his tribe to clean and professional looking when they see Jack.
4. Roger challenges them on their approach to castle rock.
5. Jack has been hunting
6. Ralph calls Jack a bloody selfish leader (i think)
7. Samneric decide to change tribes
8. He pushed a rock on him

9. I think that Roger is obviously responsible for his death, but when i really think of it, the whole group is responsible for his death too.
I think this because well Roger "put all his weight on the rock". He didn't forget that piggy was under him, and he probably was not relaxed at this time, so he did it on purpose. I think the group because they always treated piggy badly. For example, when they broke his glasses, that was not Piggy's fault, it was the groups' and how all the time, he never got to talk. If they would of treated him like he should of been treated, like a normal SMART useful person, then the glasses probably wouldn't have been taken.
I think this because Piggy is smart, and if only the group treated him better, Piggy would probably gain confidence to fight back when Jack took his glasses, or when the big rock came down, or even to help Ralph defend his side in the fight.
So you see if only Piggy was treated with respect by the group, he would most likley have his glasses, and then he could see, so he wouldnt even be in the path of the big rock.