Does anyone know why Hilarie Burton and Chad Michael Murray didn't return this season?

No one really know's but it was going around that it was because of money and that Chad and Hilarie already wanted out and I think Chad wanted to leave and Hilarie said if he did she was going with

i think it was because Chad wanted more money n if Lucas went then Peyton would have to go with him

umm truthfully its probably because of just their daily lives they are probably caught up in there own lives and focused on other things besides oth.. wich is pretty stupid if you ask me! i mean look how far oth has made it.