Apart from oblation day, new moon, and days on which tharpanam is performed, do we need to feed cooked rice to crows?

One can feed crows daily. This is not ordained by scriptures.
Notes:
Those who do Anna Vaishvadevam ritual keep the cooked rice outside so that crows and other birds will eat.
It is a rule that a clump of cooked rice to be placed for crow in shrAddham.