yellowing leaves before flush?????

I hate pulling leaves off plants at the best of times but when they are as yellow as some on these, surely they have served their purpose and need to be removed???
Also wondering why this is happening as they are 4 days away from first flush yet it looks they are cannabilising on themselves already, it's not all of them either so dont think it nute related as they've all had same the amount at same times throughout their lives, unless i need to be giving them something i'm not of course, there again, others would need it too... any advice greatly appreciated...

http://youtu.be/H5qEjRiCzsY


problem becomes apparent @ 2:00

thats normal!!! let them bitches sleep!!!!!!!!!!!!!

Don't pull leave them to be sucked dry of all the nutrients left.

hes right but youll catch me pulling some off lol n yea thats normal due to low levels of N wich is ok for bloom phase

PHEW!!!!!

cheers guys...