Praise be to Allah.
Selling beautiful birds such as parrots, nightingales etc, so as to enjoy their voices, is permissible, because looking at them and listening to their voices is a permissible aim. There is no Islamic text that forbids us to sell them or keep them, rather there are reports which may be understood as meaning that it is permissible to keep them if one gives them food and water and does whatever else they need. For example, al-Bukhaari narrated that Anas said: I had a brother who was called Abu ‘Umayr – he (the narrator) said: I think he was a weanling – and when he came he would say: “O Abu ‘Umayr, what happened to the nughayr?” – a small bird with which he used to play. Al-Haafiz said in his commentary Fath al-Baari, when listing the things that we learn from this hadeeth: It indicates that it is permissible for children to play with birds, and it is permissible to spend money on permissible things that will entertain children, and it is permissible to keep birds in cages and the like, and to clip the wings of birds, because one or the other must have been done in the case of Abu ‘Umayr’s bird, and whichever is the case, the other comes under the same ruling. There is also the hadeeth of Abu Hurayrah (may Allaah be pleased with him), according to which the Prophet (peace and blessings of Allaah be upon him) said: “A woman entered Hell because of a cat that she detained, and she did not give it food or water, or let it eat from the vermin of the earth.” If this is permissible in the case of cats, it is also permissible in the case of birds etc.
Some scholars are of the view that it is makrooh to keep birds as pets, and some of them said that it is not allowed, and they said that is because man has no need to listen to their voices or enjoy looking at them; rather this is a kind of extravagance, luxury and soft living, and it is also a kind of foolishness, because it is enjoying listening to the voice of an animal which is longing to be free, and which is sad because it is not able to fly in the sky, as it says in al-Furoo’ wa Tas-heehihi by al-Mardaawi (9/4) and al-Insaaf (4/275). End quote.