In Keiti, in the 24th and last period of the calendar for the year, there is a haú glyph (Eb6-12):

Eb5-29	Eb5-30	Eb5-31	Eb5-32	Eb5-33	Eb5-34	Eb5-35
Eb6-1	Eb6-2	Eb6-3	Eb6-4	Eb6-5	Eb6-6
Eb6-7	Eb6-8	Eb6-9	Eb6-10	Eb6-11	Eb6-12	Eb6-13
Eb6-14	Eb6-15	Eb6-16	Eb6-17	Eb6-18	Eb6-19

There are 5 feather marks on the inside of the 'bough' and 12 on the outside. The feathers on the outside presumably refer to the number of months in a year.

The feathers on the inside (hidden from sun light) presumably stand for 5 extracalendrical days, after the regular 12 * 30 = 360 days in a solar calendar.  At one time during the year we can be certain the gods will assemble, during those 5 nights when gods are born.

The observant reader will discover a 13th outside little feather at bottom left. At the 'root' there is a little remnant. Perhaps it is a recognition of the fact that 12 * 30 + 5 days is not enough - every 4th year an extra day must be added.