Manava Dharmashastra 5.22

5.22

yajñārthaṃ brāhmaṇair vadhyāḥ praśastā mṛgapakṣiṇaḥ
bhṛtyānāṃ caiva vṛttyartham agastyo hy ācarat purā //

Beasts and birds recommended (for consumption) may be slain by Brahmanas for sacrifices, and in order to feed those whom they are bound to maintain; for Agastya did this of old.