Broody leaving the nest during the day

[m0ther_g00se]

my broody duck has a nest of thirteen eggs, some up to two weeks old almost, and she's started sitting on the nest... but only in the mornings. She'll sit it at night and in the cold portion of the morning, sometimes up until i come home from school, but in the warm portion of the afternoon (starting at 1pm, it's ~80F) she'll get up off the nest and not get back on until after i go to bed (10pm or so). I see attached yolks, so there's clearly something going on in there, but I'm worried she's not sitting for long enough to incubate them properly.
she's turning them just fine, and she covers up the nest and everything when she's away from it. it's just like she's only broody for the night shift. It's the sun's job to do it during the day, right?

 

[Wyorp Rock]

Doesn't sound like she's really committed and likely you will not have any hatch.

 

[m0ther_g00se]

she's sat almost all day so far today. hoping she's getting serious about it. She only got off once when i got close to check on her, then she ate some bugs and took a drink and got right back on.
strangely enough, the number of eggs in the nest has decreased, from 12 to 9. not sure what happened there. can't find 'em anywhere else in the yard either.