Broody hen with duck eggs

Treacle, my broody hen is on day 7,sitting on 6 rather large duck eggs.  The Welsh Harlequin duck eggs are a fabulous size, lovely and clean and I hope, fertile.
I have never hatched duck eggs before, let alone under a broody hen so I have had to read up on ducks.

Firstly 28 days is a long time, I get quite impatient but hopefully it will be worth it, secondly, they have slightly different requirements in an incubator when compared to hen eggs, specifically temperature.

My research has suggested that these will not be an issue under a broody hen.  How then does she know to site for 28 days and not get off at say day 23 or 24 when she would perhaps naturally do so if  none of her own eggs hatch?  And does she somehow increase temperature and humidity?

I can't answer these questions, but it seems she just gets on with the job.
It is not an ideal time of year to try and hatch, in fact this morning, temperatures seem to have dropped.  I hope the hatch is successful and I will add more bedding for her to nest in to try and help with the dropping temperature.

Welsh Harlequin Ducks

Time will tell if I get chance to candle the duck eggs.  It will just be luck if I am there when Treacle leaves the nest.

As we head into September the quail are slowing down, with only two eggs daily, it's quite a shock to my boys who love them boiled as a snack. On the positive side, the hens at the plot are laying and providing a nice supply of bantam eggs.  I am still waiting for the crested legbar to lay.  They are now 22 weeks so I would hope they are on the verge of laying our very first blue eggs.
Fingers crossed.

Thanks for reading.