Unsuccessfull broody hen

My broody hen Gherti has been sat on her eggs for almost a month now, another hen Mariella who started after her has hatched hers and is now the proud mother of 7 hyper chicks. But nothing is happening, ive listened to the eggs and heard nothing. She's had babies before, and there isnt just her eggs under her. There was 13 and theres now only 5. I keep finding broken shell lying around. I was wondering whether anyone had any ideas as to whats happening with the eggs? And also what I should do next? Ive wondered about putting a couple of Mariellas under her as 7 is a lot of babies! or trying to find some day olds to put under her. Shes put so much effort in I havn't got the heart to take her eggs and leave her babyless. She looks really miserable and I don't know what to do for the best? Help?! 

I havn't got a lamp but my friend does. But I'd rather they had a mum to look after them! How sentimental are chickens? Am I being a bit soft thinking she's depressed and that Mariella in the next house surrounded by babies is making things worse?

Thats lovely! The other thing is will Mariella then get upset that I've stolen her babies? Is 7 too many? Its not is it? I will try and find her some chicks tomorrow! Ill leave Mariella alone. She's already angry at me for taking her empty eggs.. How long can eggs go with out being sat on and still be babyfull? 

I will try that!! Thankyou ever so much!  :happy: