afters hours and hours of wiping I managed to down ony.
I used the feign death bug for the big adds and most of the whelps. biggest issue is getting all the whelps onto the pet while having fd up for the big adds. delaying the first whelps with a long fd (till they're all the way back in the egg chambers) helps a ton. after this it also seems that there are less whelps coming, but this isn't always the case.
spirit bond perfectly takes care of the fireballs ony throws at random raid members.
I also tried downing her the regular way. alot of times I didn't manage to keep my pet alive when 40 whelps are on it. when I managed to get through this and kill the first big one, there isn't alot of time to dpsing ony.
second whelp wave already came at like 55-58% of onyxias health pool and always killed me. due to the whelps not spawning in the same place and just coming one by one its really hard to get all of them onto the pet. then you take a lot of damage from whelps and this + the fireballs is too much with just spirit bond for self healing.
I guess it might be possible with perfect execution and really clever use of fd, but it's really really hard.
spec:
Talent Calculator - World of Warcraft
turtle spec:
Hunter Pet Calculator - Wowhead
video:
YouTube - 85 hunter soloing onyxia10