Hi,
I would go ahead and discard the egg and any others she might lay. There are some things you can do to discourage nesting and egg laying. It’s hard on a hen to form and lay eggs, and especially for an older hen. Making these changes can help. If you aren’t planning to breed them, it’s probably better to have them in separate cages and let them interact outside of their cages.
Keep in mind that in the wild for breeding, they need longer daylight, warmer weather, abundant food, and a quiet, private environment. The goal is to reverse these conditions.
Limit their light to 8-10 hours by covering the cage early each evening
Do not give them anything to use as a nest – no bird huts or tents, no box, bowl, etc. If she decides to sit in a food bowl, remove it and replace with smaller cups.
Do not give them anything to shred such as paper or cardboard.
Rearrange the toys in the cage frequently.
Move the cage to a different place in the room. Move the cage about once a week, or whenever they show signs of nesting – settling on the cage floor for example. This disrupts her idea of having a stable place to lay eggs and raise chicks.
If you feed a lot of fresh foods, stop offering any for a couple of weeks, and then only offer them in small amounts about 2 or 3 times a week. You can resume normal feeding later when the birds aren’t being hormonal.
When they are let out of the cage, do not let them get in any dark cozy places and don’t give them free roam. When you let them roam around, this mimics searching for a nesting site.
When you handle them, limit any petting to only the head and neck – do not pet a bird on the body. Only a bonded mate is allowed to groom the body. We can’t be a mate, so touching the body is off limits.
If there is no metal floor grate, then do not use any bedding or paper in the cage tray – leave it bare and clean it daily.
Thank you for asking Lafeber,
Brenda