Is it compulsory to wash all the hairs of the beard whilst performing wudu?
It is compulsory to wash all the hairs of the beard which are apparent and easy to wash. As for those strands that are short or hidden, then it is sunnah to wipe them with wet fingers. If a person has a thin beard it is compulsory for him to rub the skin of his chin as well.
And Allah ﷻ knows the best
Imam Ahmad Rida Khan رحمة الله تعالى عليه
Translation by Dr Musharraf Hussain Al-Azhari Translator of Majestic Quran, www.majesticquran.co.uk