Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa., – Volume 13, Page 34, Question 2 of Fatwa No.18248
Question: My brother trades in small birds. Is this permissible or not?
Response: It is permissible to sell small birds, since this comes under the general heading of permissible sales.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet ﷺ and his family and his companions.