Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.056.
Section : Clipping Some Hair Only.
‘Ata reported that if a person in the state of ihram pulled off three hairs or more, he must slaughter a sheep in compensation for that. This was reported by Sa’id bin Mansur. Ash-Shafi’i also reported from ‘Ata that if a muhrim pulled one hair he must give one mudd (A dry measure), and for two hairs two mudds to the needy, but if he pulled more than two hairs then he must offer a sheep in sacrifice.