Ideas:

1. Here we should notice that both wings are seen (in spite of this bird being shown in side view). This is certainly a sign. I guess that it is a sign of young age, perhaps we should say chicken age. This chicken is perhaps going to grow up into a big 'tired old bird' in due time.

2. Another sign pointing towards chicken age is the short beak. As a rule youngsters of all sorts of animals have a more rounded physiognomy than adults. I suppose this can be explained from evolution, once having had us all in eggs. It takes some time to grow away from the egg-form into the adult shape.

3. Notice the pattern: the 1st glyph in a period is a chicken just hatched and the 4th glyph is already showing signs of old age (long beak and heavy head). It reminds me of the similar pattern in Sunday: up full of life in the morning and down thoroughly exhausted in the evening. This is a pattern of life.

4. But the 4th glyph in the 8th period (see above) is also showing clear signs of rebirth. I think this is the same thought that the Mayas had about a new coming time period making itself noticed already at the end of the old time period. Cfr also my ideas about Monday.