I had a 6 pool which i scouted last eariler on today but managed to hold it, if i see 6 lings streaming towards me i'll throw a second gate instead of a cyber down while chronoboosting my 1st zealot out to complete the wall, my first gate is always on 13
if his drone is in your base and attempting to stop you walling off a 6pool is coming i've only noticed stupid zergs doing this as it gives it away too easily and u can prepare more easily for it.
also on 4 player maps send your 9 probe clockwise or anti clockwise which ever you prefer and if you feel uneasy or worried send a second scout in the opposite direction,