You can put some branches, blocks, logs, and other things for them to play on. One big help would to be: buy a bale of hay/straw. Bust it up in the run till there is about 6-8 inches of hay they can scratch thru. It will help your coop/run health plus give the birds something to investigate/play with. If you can't put it all in this month, you can store it, then put some more in next month.
They'll love it! I guarantee!
Thanks, that's a cool idea, I'm sure they would love, but I have no run. I have a large pen, soon to have netting over it, and the coop is too small for something as large as a log. There is a foyer, about 8 inches wide and three feet long, then there is the main room where they sleep. I think it's about 2x3 feet. Very small for them, but we are building a new one with much more space. The one they are in now doesn't even have roosts! One of the reasons it's so small is because it was intended for our dog, but she just jumped over the fence and never went into the house.
It was so cute to watch them as chicks in the brooder box. I gave them little blocks, ramps, and platforms to play on.
I do sprinkle feed around the ground where they hang out by the house in the day time, which can keep the occupied for a while. Sometimes they come with me into the field to eat berries, but there is nothing for them to do in the night but sleep. Sleep they do, but if boredom is causing them to bury their eggs it's only boredom in the night.
I was thinking today of using some of the logs and materials lying around to make a playground for them like I did when they first started going outside. It had bamboo stick roosts, a ramp up to an elevated nest, a lower board to perch on, and apples hung by strings. I would love to do it in a bigger version, but I just need to find a good spot.
The new coop will have roosts, and more room means more fun things I can give them.
Back to the subject.
What else could be causing them to bury their eggs?