I have 4 hens. Two are 3.5 years old (Leghorn and Rhode Island Red) and two are just 20 weeks. Both the older hens moulted late last year/early this year and went off the lay. The leghorn started laying again about a month ago and the Rhode Island Red started squatting and checking out nest boxes earlier this week. I noticed yesterday that my RIR was spending a lot of time in the nesting box and when I checked on her I could see that she was straining but no egg was produced. This morning both the older hens were taking turns in the same nesting box and when I checked it after the RIR left it there was an egg, still very warm. It looked about the same size and colour that my Leghorn lays. We went out today and when I came back this afternoon and checked the nesting boxes there were the remains of a crushed egg in the box that the RIR was straining in yesterday. The shell fragments are pretty much the same colour as the Leghorn's eggs but the RIR's eggs were also a similar colour when she was laying last year. I'm worried that the RIR may have broken the egg inside while she was trying to lay. I didn't see blood or detritus around her vent and she seems fine, foraging as usual. What is everyone's advice?