One cockatiel owner was told that seed only diets were bad so he put his cockatiel on a pellet only diet. Unfortunately, this led to the cockatiel getting gout, so he had to be on
allopurinal for the rest of his life. Roudybush fortunately makes a pellet diet
(by prescription only) that is good for birds who suffer from high uric acid levels. At $10 a lb
(including shipping), well I can say that it works.
(and works over Zupreem Natural which is not formulated for birds with health issues) Harrison's foods are supposedly good for birds who suffer from liver and kidney problems as well, but for the time being I remain skeptical.
Even single hens lay, but you have been furtinate indeed that she hasn't become an egg layer and I hope that continues! Since the hen I last mentioned laid an egg, I've had another hen, a bourke parakeet, that laid an egg yesterday. She's 12-15
(?) years old, too... she's hit the approximate age mark of life expectency already!
(well, 10-20 years, probably not longer... her parents died at about her age, the hen surviving about a year longer than her mate, lost both due to different issues however)
I've heard of budgies who have lived to 18 years on seed only diets, and others don't make it past 6 years at best. Could be due overbreeding, under-age breeding, inbreeding, breeding genetically "unhealthy" birds, etc. So life expectency certainly does vary. We've gone from seeds and monkey chow for the larger parrots constitutes as a good diet, to pellets are best, and now into pellets are good but *maybe* not so great for some species... so yes, we are still figuring things out!
I'm sure I'm just repeating info here that you already know... but here's some videos of various species laying eggs!
So what exactly does egg laying look like? Well, I've searched Youtube for some videos to show you the process!
YouTube - Budgie laying an egg
YouTube - Lineolated Parakeet hen seen laying an egg
YouTube - Budgie Laying An Egg
YouTube - Hyacinth macaws laying first egg.
YouTube - Poquito's Egg laying
YouTube - Bella laying an egg part 2 (what one should not do.... stroking, petting, touching etc of hens in a potentially sexual way)
YouTube - Parrotlet Laying Egg
This video goes to show why it's important to know the sex of your bird. Even if you never plan on breeding, some health issues can be discovered much faster if you know for sure if you have a male or female parrot.
YouTube - sick cockatiel