The offering of food to Crows , is not limited to Sraddha days. Food has to be offered to Crows daily. Food has to be offered to Deities daily. Freshly cooked food is to be offered. There are different views on whether one can offer the food offered to Deities, Naivedya, can be offered to Crows as Crows represent Pitrus
As most of you are aware there are Four Vedas.
Rig,Yajur Sama and Atharva,
In addition to this there are Vedangas , which contain other Sciences like Archery, Astronomy and the like.
Based on the station of Life of an individual. the Life of an Individual was divided into four parts.
Brahmacharyam, Period of Study,
Gruhastham ,period of Married Life,
Vanaprastham Preparatory Period for Renunciation and handing over of family responsibilities and
Sanyasa, Period of Renunciation.
Please read my posts on this under 'Hinduism/Indian Philosophy)
Normally the child is sent for learning at the age of Five after Yagnayopaveeda ceremony to the teacher where the child stays and learns.
The period of study:
Nine years, called Adhama, not very auspicious,
Twelve Years,Madhyaman, Acceptable,
Eighteen Years,Uthamam, The best.
There were also people who were doing the Adyayana, or the learning of the Vedas, for thirty-six years or through out their Life.
One can remain a Brahmachari, without marrying through out Life learning the Vedas.
There were Two Terms in a year.
The First Term is called 'Upakarma' Months.
The Second Term is for Seven moths called 'Uthsarjanam or 'Uthsargam'