Blue tit nest

  Hi there, 

We've found a blue tit nest on our land, unfortunately they have got inside a stone statue. I will attach a picture, the parents are going in and out no problem but I don't think the chicks will be able to fly out when ready. There was 6 chicks in there, now I can only see 4 and I believe there are some bodies inside now. I can't really have good look as I don't want to disturb them anymore. Do you think they can leave? Also any help or advice would be great. Also it was very hot yesterday and I'm worried could they of overheated.

Thanks 

Kayleigh