Recently I noticed that my Silver Sussex hen had gone broody so I decided to replace the infertile chicken eggs she was sitting on with a clutch of 5 fertile eggs from my Indian runners. Due to space issues, I have had to leave her in one of the nest boxes with the other chickens which meant that every day I would have to go out and collect the chicken eggs from under her as otherwise she would be sitting on too many for her to be able to incubate them all. Unfortunately, I recently went away overnight and asked my mum to take the chicken eggs from under her, however when I got home she had not done this and two of the five duck eggs had been left by the side of my broody hen as she was sitting on too many eggs (she had replaced the duck eggs with three chicken eggs). When I went to pick them up they were very cold and could have possibly been like that for up to 24 hours and as I live in the UK the temperature can drop quite a bit overnight although in the day it has been about 22 degrees celsius (about 70 fahrenheit) where I live. Not knowing whether to put them back under her or not I marked them with a pencil so that I could know which ones where which and do some research to find out what I should do but I couldn't find a lot.
Should I still try to incubate them with my broody or would this be a bad idea? If anyone has any advice on what to do any replies would be much appreciated.
Thank you in advance for any help.