Ibn Jurayj (may Allah have mercy on him) said: The best I have heard about ostrich eggs is the hadith of Abu al-Zinad, from al-A'raj, from Sayyiduna Abu Hurayrah (may Allah be pleased with him), that the Messenger of Allah (peace and blessings be upon him) said: "For every egg, a day's fast or feeding one poor person."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10017