Śatapatha Brāhmaṇa ("of a hundred paths") 7.5.2.2

7.5.2.2

yadvevokhāyām | yonirvā ukhā paśavaḥ paśuśīrṣāṇi yonau tatpaśūnpratiṣṭhāpayati tasmādadyamānāḥ pacyamānāḥ paśavo na kṣīyante yonau hyenānpratiṣṭhāpayati

And as to why (he puts the heads) in the fire-pan;--the fire-pan being a womb, and the heads of the victims being animals, he thus establishes the animals in the womb: hence animals, though being eaten and cooked, do not diminish, for he establishes them in the womb.