Runner sitting on viable eggs!

[duckcrazy]

I was away for 7 days and my helper did not collect the eggs. Upon returning, I found my runner duck determined to hatch her clutch; she hardly ever leaves the nest. After candling the eggs, I am sure that there are at least 3 viable eggs growing chicks. Here is my question: If by some chance any of the eggs hatch, can I leave them for the mother to raise or do I have to put them in an enclosed building with heat lamps?
It has been in the 90s here.

 

[duckyfromoz]

Runners arent known for being mothers- but they can still do a great job... it really does just depend on the duck. The main thing I would suggest is to provide the mother with a safe environment to raise the ducklings- but also watch her closely to make sure she is looking after them well enough. Give her a chance first- but you may need to raise them in a brooder yourself.