I’m a compete novice, but I noticed yesterday that there were blue tit chicks in one of my bird boxes (I’d been away for a week). They were making a fair amount of noise so I presumed they were being fed ok. As the day went by I realised I hadn’t seen a parent feed them, but by the evening they could still be heard chirruping. I searched the internet and was assured that as long as they were chirruping the chances are they were being fed. however this morning it was completely silent. I waited a while before checking the nest and discovered six fairly large blue tit chicks all dead and the remains of two much smaller ones. It really upset me and I am now thinking I could have done more, perhaps taken them to a wildlife rescue.