“bhoota yagyam भूत यज्ञम् “means offering food to beings and creatures like animals, birds,etc.
It is also called “bali haraNa बलि हरण”, where bali here means a portion of cooked food and haraNa means offering/keeping of food .
Taittireeya AraNyakA , Prashna 2, AnuvAka 10 says:
oÉýÍsÉóèहर॑ति॒ तद्भू॑तय॒ज्ञस्सन्ति॑ष्ठतॆ॒ rÉSèoÉëÉÿ¼ýhÉãprÉÉãÅ³ÉýlSSÉþÌiÉýतन्म॑नुष्यय॒ज्ञस्सन्ति॑ष्ठतॆ॒ rÉjxuÉÉÿSèkrÉÉýrÉqÉkÉÏþrÉÏýiÉ MüÉþqÉmrÉ×ýcÉðrrÉeÉÑýxxÉÉqÉþवा॒ तद्ब्र॑ह्मय॒ज्ञस्सन्ति॑ष्ठतॆ॒ ।
There are 5 mahAyagyAs for a house holder. They are 1. dEva yagyam 2. pitRu yagyam 3. bhoota yagyam 4. Manushya yagyam and 5. Brahma yagyam. Deva yagya consists in doing hOmA for the dEvAs by kindling the fire with samid. pitRu yagyam consists in offering oblations to pitRus by saying the word swadhA. Bhoota yagyam consists in offering food to beings and creatures. Manushya yagyam consists in offering food (annam) to brahmaNas (or guests). Brahma yagyam consists in reciting the Rug, yaju: and the sAmA verses which one has learnt. This recitation is called (swAdhyAyam) .
Householders (gRuhasthas) must perform bhoota yagyam.
A householder must perform bali haraNa after performing dEva yagyam/vaishvadEvam.
Apastamba Dharma Sootram 188.8.131.52
In bhoota yagyam, bali has to be offered on the ground and not in the fire. The place must first be wiped with the hand, then water must be sprinkled, then the bali has to be kept and then water is sprinkled again around the bali. (parishEchanam)
Manusmriti 3.87 to 3.95
एवं सम्यग् हविर् सर्वदिक्षु प्रदक्षिणम्।
इन्द्र अन्तक अप्पति इन्दुभ्य: स अनुगेभ्यो बलिं हरेत् ॥
evaM samyag havir sarvadikShu pradakShiNam|
indra antaka appati indubhya: sa anugebhyo baliM haret ||3.87
After having duly offered the sacrificial food to the dieties of vaishvadEvam, let him throw Bali offerings in all directions of the compass, proceeding from east to the south, to Indra, Yama, Varuna, and Soma, respectively as well as to their servants..
मरद्भय इति तु द्वारि क्षिपेद् अप्स्वद्भय इत्यपि।
वनस्पितिभ्य इत्येवं मुसल उलूखले हरेत् ॥
maradbhaya iti tu dvaari kShiped apsvadbhaya ityapi|
vanaspitibhya ityevaM musala ulookhale haret ||3.88
He shall then scatter some food near the door for the MAruts.
Some food in water for Water(Apa:)
Some food on to the mortar and pestle for the trees (vanaspati)
उच्चीर्षके श्रियै कुर्याद् भद्रकाल्यै च पादत।
ब्रह्म वास्तोष्पतिभ्यां तु वास्तुमध्ये बलिं हरेत्॥
uchcheerShake shriyai kuryaad bhadrakaalyai cha paadata|
brahma vaastoShpatibhyaaM tu vAstumadhye baliM haret||3.89
Near the head (of the bed) he shall make an offering to Shree or Shri (fortune), and near the foot (of his bed) to bhadrakaali;
In the centre of the house let him place a Bali for Brahma and forVaastOShpati (the lord of the dwelling) cojointly.
विश्वेभ्यश्च एव देवेभ्यो बलिम् आकाश उत्क्षिपेत्।
दिवाचरेभ्यो भूतेभ्यो नक्तंचारिभ्य एव च॥
vishvEbhyashcha eva devebhyo balim aakaasha utkShipEt|
divaacharEbhyo bhootEbhyo naktaMchaaribhya Eva cha||3.90
Let him throw up into the air a bali for all the gods, vishvEdEvAs of the day time,
And in the night let him throw in the air a bali for beings roaming in the night.
पृष्ठावस्तुनि कुर्वीत बलिं सर्वात्मभूतये।
पितृभ्यो बलिशेषं तु सर्वं दक्षिणतो हरेत्॥
pRuShThaavastuni kurveeta baliM sarvaatmabhootaye|
pitRubhyo balisheShaM tu sarvaM dakShiNato haret||3.91
Let him offer a Bali on the first floor to all beings ( Sarvatmabhoota )
And out of what is left out, let him offer it in a southerly direction for the manes.
शूनां च पतितानां च श्वपचां पाप रोगिणाम्।
वयसाणां कुर्मीणाम् च शनकैर् निर्वपेद् भुवि॥
shoonaaM cha patitaanaaM cha shvapachaaM paapa rogiNaam|
vayasaaNaaM kurmeeNaam cha shanakair nirvaped bhuvi||3.92
Let him gently place on the ground those helpless wandering with diseases and to animals like dogs, crows, and insects.
एवं य: सर्वभूतानि ब्राह्मणो नित्यम् अर्चित।
स गच्चति परं स्थानं तेजोमूर्ति: पथा ऋजुना॥
EvaM ya: sarvabhootaani braahmaNO nityam archita|
sa gachchati paraM sthaanaM tejOmoorti: pathaa RujunA||3.93
That braahmana who thus daily honours all beings, goes, endowed with a resplendent body, by a straight road to the highest dwelling-place (param).
कृत्व एतद् बलिकर्म एवं अतिथिं पूर्वम् आशयेत्।
भिक्षां च भिक्षवे दद्याद् विधिवद् ब्रह्मचारिणे।
kRutva etad balikarma evaM atithiM poorvam aashayet|
bhikShaaM cha bhikShave dadyaad vidhivad brahmachAriNe|3.94
Having performed this bali offering, he shall first feed his guest and, according to the rule, give alms to an ascetic or a brahmachAree.