Hmm, I'm still a newbie with Broody hens myself - my girl is on her first nest, which started out with 11 eggs, and then two exploded! They were rotten, and I suspect the gases built up in them and 'bang!' I wonder if that's what happened with your eggs, as opposed to the Broody 'breaking' them?
Baring in mind I am no expert....I would quietly remove the hen from the nest, whip out the wet and smelly hay, replace it with fresh hay and quickly wipe the eggs down with a warm damp cloth to remove most of the smashed egg mess and smell. Make sure you have everything ready before you start so as to minimise the time Broody is off the nest, and do it when it's starting to get dark. Then pop Broody and the eggs back on the nest and hope for the best.
You don't say how long she has been on the nest, but if you are at 7+ days I would recommend candling the eggs. Removing rotten eggs minimises the chances of future explosions, and in hindsight I really wish I had done that! I was very much against it at first, but two exploding eggs will change your mind pretty darn quickly! Remove any eggs that don't show signs of life, and keep the viable ones. There are lots of pics on this site to help you determine what is a good egg and what is bad.
Generally speaking, if you do the candling at night (or at dusk, like I did) it is not too upsetting for Broody. Just make sure you have everything ready before hand, and a helper to assist you to sort out the eggs is a good idea too. Also, 16 is a lot of eggs, so maybe next time aim for 10-12 for a full-sized hen to minimise crowding. Broody has to be able to comfortably cover the eggs and have space to move them around.
I think that's about it. Make sure she has access to food and water, and a bit of space to stretch her legs. It might also be a good idea (if you haven't already) to separate her from any other birds you have. If you can section off a space in the main coop she can still be a part of the group, but have her own space too.
Good luck, and keep us updated!
- Krista
