Please note that I am not an avian veterinarian and I am not an expert on cockatiels. I am sharing my own experience with my own cockatiels in preventing and controlling egg laying spanning over twenty years. The best person to work with is a qualified, experienced avian veterinarian. This is not medical advice and is not intended to serve as a substitute for veterinary medical consultation.
For those in the NE USA it's hormone time for cockatiel hens. Mine are getting itchy and I'm removing anything which could be used as a 'mate' or a nest as well as anything providing too much cover such as happy huts, those hanging tents. Back off on handling and don't even give crest scritches for the next 3 months. I don't know about other parts of the USA or the rest of the world but for Northeasterners it's hormonal time and time to start environmental therapies and considerations to either prevent egg laying or keep it to a normal number of eggs which is almost always three to six.
If you are keeping on lights more than about an hour after it's dark out please don't. If you are handling daily to include lots of time with the tiel hen on your body, be it your shoulder or arm limit tiel hen on body to only a couple minutes maximum a couple times a week.
Change around the inside of the cage. Rearrange most of the perches and toys. Save moving the cage to a different spot in the living room or to another room for down the road.
Diversion is good but also don't do so much drastic diversion at once that you frighten the tiel hen.
The goal is to keep them just slightly confused in a happy new way not an all out shock diversion.
Cockatiel hens are more likely to lay when they are very content and settled and by environmental diversion she's less likely to lay and if she does lay more likely to lay a normal size clutch.
This post is NOT about breeding. This is about preventing chronic egglaying and egg binding in cockatiel hens. It's also not about being mean to cockatiel hens.
This is the time to put new toys in the cage. Not prolong daytime lighting by more than one hour with lamps on in the room with the tiel hens.
Feeding should be great but don't power feed tiel hens right now. The more high quality, high nutritional density foods tell them they are safe food wise and they lay.
Keep foods nutritious for sure but be more heavy on veggies and even apple and fruit and yes, quality seed mixes and as much as I don't like to say it and I'm sure I'll get flamed for this, if your tiel hen eats pellets, back off just a little with the pellets and replace some of the daily pellet intake with green beans, corn, peas and any veggie she eats.
It's not about starving them or letting them be hungry at all. It's about feeding them low nutritional density foods as this will work with their instinct and tell them it's not time to lay eggs as food isn't 'meat and potatoes' foods and sometimes prevents egg laying or reduces the eggs laid to one normal size clutch.
High protein high fat foods such as sunflower, peanuts , peanut butter, super great high potency pellets are not foods to be feeding a cockatiel hen now as these foods tell her she has rich food in abundance to feed her chicks.
Normal pellets in small amounts, fresh tiel seed mix without sunflower in small amounts and lots and lots of vegetables however she likes them, raw, cooked soft, and apple and other safe fruits tell her she is getting food not heavy in protein and fats and she by instinct won't lay or lay only a normal clutch without 'power foods' to provide her chicks with by eating power foods to regurgitate back to them.
Power foods or power feeding encourages egg laying during winter months in the NE USA in cockatiel hens.
Don't starve her or ever let her go hungry or not fill up her belly just provide her with low protein, low fats food. In the wild in Australia tiels by instinct either don't lay or lay fewer eggs when the food supply isn't the best. They lay more eggs or double clutch when food is plenty and abundant in the wild. So to work with the instincts to prevent laying or keep it a normal clutch keep foods fed low protein, low fat with more veggies and salads and only moderate amounts of normal pellets and/or tiel seed mix without sunflower or peanut chips.
If you are gone during the day letting on a televsion on a bouncy type channel such as a rock and roll channel or any channel with different types of sounds helps to divert them. The radio left on to a station with all kinds of music is good also.
Remember they also will lay right off the perch and don't have to have a nest or nest like area. I've witnessed a few hens laying right off the perch.
If she does lay eggs and sit on them it will most always be in the corner on the pan or grate. Leave her alone for a week or until she is done laying. Get the eggs out and hardboil them as you would a chicken egg for hard boiled eggs. Let them cool and put them back in. This preserves the egg much longer than raw and many hens simply abandon the eggs after a couple weeks and forget about it all and don't lay again for another year. She simply gives up when the eggs don't hatch as well as dehydrate on her and calls it quits until the outside weather tells her to breed again.
Every avian vet I've had since 1988 has told me half of tiel hens die before the age of 4 from chronic egglaying both treated and untreated. Not all tiel hens are chronic layers. Some drop a few eggs during hormonal times and don't even sit on them and couldn't care less. Some sit tight on them on the cage floor or grate.
In the NE USA cockatiel hen hormones can kick in anytime from Dec. to March. This is an early year for my tiel hens and those of others I know face to face in the NE USA. I have no idea of other areas of the USA or abroad.
Also, and not to be explicit or rude but when she puts her head down and her tail almost straight up in the air DO NOT pet her or even gently pick her up. Ignore this behavior. Any touching of her at all while she is in this position gets her all fired up to lay eggs. Simply ignore this posturing as it only lasts a few minutes.
It's a cruel and unfair world for these majestic little cockatoos living in captivity as they are only doing what they are supposed to be doing. It's also instinct and you cannot actually teach them not to do this but you can humanely divert them as much as possible and you have to.
Also while most all male tiels are not female beaters or female aggressive there are a few that bully a hen during her high hormonal times. I've never had a male tiel physically attack a hen but I've had a few fellows bully a hen by placing himself between her and the food cup or stalking her all over the cage and making mating advances towards her which she as a captive hatch bird doesn't always understand his advances and bites his feet and toes and this makes him back off, but not for very long.
If you are housing hens with males you need to make sure, factually that he is not an aggressive male during this high hormonal time for her and also him. Have a cage for him to live in until breeding season is over. My small flock of tiels is coed with not any issues at all except for breeing season and then I put the fellows in a small bird large flight cage being 4 feet by 2 feet and they are fine.
Hens caged with hens can be a good thing in that one hen may lay a clutch and permit another hen to sit on her eggs thus the helper hen doesn't lay any eggs. This also reduces stress on the hen having laid the eggs as the helper hen and her take turns sometimes sitting.
I've dealt successfully with many chronic layers over the years, all given to me by people not wanting to deal with them, in simply housing all the hens together during the start of the hormones each winter and in my small flock of tiels I've had good results in say, two or three hens laying a clutch and then each permitting another hen to sit on her eggs and the helper hen doesn't lay her own clutch. This is one good potential outcome of housing hens, especially those with a histroy of chronic egg laying and/or egg binding and it's a good outcome as helper hens don't lay and they sometimes change as in one year the hen is the layer and then the next time the layer hen is the helper hen not laying.
This is only my experience with my hens and is not intended to be a substitute for professional consultation with an avian veterinarian. I'm not an expert and I am merely sharing what has helped my hens to not continue with chronic laying. The best person to get information of dealing with laying hens and chronic layers is a qualified, experienced avian veterinarian. This is just my .02 based on my experiences with my tiels and I'm not an expert, a vet or a professional aviculturist.