She may be trying to lay an egg. They do not need a male to produce eggs. It is an emergency, and she should be placed in a warm box as described above. That will help. And make certain she has plenty of fresh water and food.
If there is a shelled egg, you will be able to feel it in her abdomen. Warmth, calories and hydration are the main emergency measures you can do at home.
The vet will likely give her calcium injections, fluids, and may assist delivery of an egg, if that is the problem.
There are other possibilities but an egg would be the first thought.
Photoperiod, diet and reproductive stimulation need to be altered to perevent reproductive issues in the future. She should have 12-14 hours of dark, uninterrupted, quiet sleep at night; a good diet with no seeds; and no nesting or sexual stimuli.
great tips for egg-laying:
Birds should be on a high-quality, preferably prescription, pelleted diet: I prefer High-potency Harrison's
In addition, they should be offered dark leafy greens, cooked sweet potatoes, yams, squash, pumpkin; entire (tops and bottoms) fresh carrots and so forth. No seeds (and that means a mix, or millet, or sprays, etc. etc.) and only healthy, low-fat high fiber people food. A dietary change should be closely monitored and supervised by your avian vet.
Birds should get 12-14 hours dark, quiet, uninterrupted sleep at night. Any less and they can suffer from sleep deprivation and associated illnesses. They should be covered or their cage placed in a dark room that is not used after they go to bed.
The cage material should be cleaned everyday, and twice a day if the bird is really messy. Paper towels, newspaper, bath towels are ok. Never use corn cob, sawdust, wood chips, or walnut shell.
Food and water dishes should be cleaned and changed daily. Keep one set cleaned while the other is in use.
Fresh, perishable food should be placed in separate food bowls. Remove fresh food from the cage after a couple of hours to avoid spoilage.
Change cage papers daily, and clean the grate and tray weekly.
Clean food debris or droppings from toys and perches as needed (which can be as often as once a day).
Grit is not necessary for birds, and will cause digestive problems and death. The best sources of minerals (and vitamins) are leafy greens. Never give grit, gravel sandpaper or cement perches. A bird will eat those to excess when it is not feeling well or if there is a nutritional deficiency. They do not need it at all (an old myth from the poultry days, even poultry do not need it). It can cause an impaction and lead to serious or fatal consequences.