"I came to the Prophet and asked him about the sacrificial meat. I heard him say: 'For a boy, two sheep, and for a girl, one sheep, and it does not matter if they are male or female."' (Using translation from Nasāʾī 4217)  

أَتَيْتُ النَّبِيَّ ﷺ بِالْحُدَيْبِيَةِ أَسْأَلَهُ عَنْ لُحُومِ الْهَدْيِ فَسَمِعْتُهُ يَقُولُ «عَلَى الْغُلَامِ شَاتَانِ وَعَلَى الْجَارِيَةِ شَاةٌ لَا يَضُرُّكُمْ ذُكْرَانًا كَانَتْ أَمْ إِنَاثًا»  

I heard the Prophet (nay peace be upon him) say: Let the birds stay in their roosts. She said: I also heard him say: Two sheep are to be sacrificed for a boy and one for a girl, but it does you no harm whether they are male or female. (Using translation from Abū Dāʾūd 2835)   

النَّبِيِّ ﷺ قَالَ عَنِ الْغُلَامِ شَاتَانِ وَعَنِ الْجَارِيَةِ شَاةٌ لَا يَضُرُّكُمْ ذُكْرَانًا كُنَّ أَمْ إِنَاثًا وَسَمِعْتُهُ يَقُولُ أَقِرُّوا الطَّيْرَ عَلَى مَكَانَاتِهَا