I'm absolutely done with plastic fake eggs! This is the fifth or sixth time I've had to replace them.
The trouble with plastic fake eggs is that bush rats try to eat them by opening the end, just as they do with real eggs. Net result: chewed up half-eggs. Even if they don't make a huge hole, they take them away from the nest, and eventually all my plastic eggs disappear.
To teach hens where to lay, some people use golf balls, but they're not much more durable than plastic eggs, and they don't fool 100% of hens when it comes to setting a broody.
At the moment I've got a broody hen I want to move to a ratproof aviary, and she's so fussy I know she won't sit on golf balls.
Ceramic eggs are ideal, but aren't that easy to find.
That's why I've made these:
They're a bit rough round the edges, but only took 10 fiddly minutes to make, and cost about 20c each (that being the amount of plaster-of-paris I used from a $4 bag).
I simply took 4 eggs and chipped a 1cm hole in the fat end with a sharp knifepoint. Then I drained out the contents after a quick swizzle with a skewer to break up the yolk. (The contents became scrambled eggs.)
After rinsing the insides out fully, I left the shells to drain in egg cups while mixing up the plaster. I made it about the consistency of custard and syringed it into each cleaned-out eggshell using a 10ml syringe (20 or 50ml would have been easier). After a few shakes to dislodge air bubbles I sat each egg hole-upward in an egg carton, topping up with a little extra plaster-of-paris as the stuff began to set (as plaster sets in a mould it tends to sink a little).
When all eggs had hardened I sanded off excess plaster and painted the eggs with some leftover house acrylic (which usefully enough was beige).
There are a few rough spots, and if I cared enough I'd give them another acrylic coat, but I think these will do. They'll behave and feel like eggs to a hen, and a few smudges will merely look like nest grime.
As plaster eggs are porous, they may need repainting to remove mould spots in future. And of course rats may still have the odd experimental nibble. But with four fifths of a bag of plaster left I can always make more.