Q: Should one intending to make Qurbani clip his/her nails and shave his hair in the first ten days of Zul Hijjah?
A: TRIMMING OF NAILS AND HAIR DURING THE FIRST TEN DAYS OF DHUL HIJJAH FOR ONE INTENDING TO MAKE QURBANI
HANAFI MADHAB: It is Mustahabb (meritorious, preferable) for one intending to make Qurbani not to trim the nails and not shave during the first ten days of Dhul Hijjah. (Raddul Muhtaar V6 P185). If one does trim, etc. no sin will be incurred.
SHAAFI'EE MADHAB: It is Sunnah for one intending to make Qurbani not to trim the nails and not shave during the first ten days of Dhul Hijjah. (Mughnil Muhtaaj V4 P283). It will be Makrooh to trim without need.
NOTE: It is Waajib (compulsory) to remove hair from the armpits and pubic hair at least once every forty days.
According to both Madhabs it is not permissible to leave it for forty days or more. So if during the first ten days of Dhul Hijjah, a person's forty days are up, it will be compulsory on him/her to remove the hair. Waajib will take priority over a Mustahabb or Sunnah.
(Mughniul Muhtaar 3:283; Fiqhul Ibaadaat, Shafi 1:799; Raudhatut Talibeen 3:210, 234; Al Fataawa Al Hindiyah 5:357; Raddul Muhtaar 6;185)