Diet Conversion for Birds
Most people are learning these days that seed alone is a very poor diet for birds. In fact, the experts are almost 100% agreed on this. Whether you wish to get your bird to eat more vegetables or pellets, or a mix of both, this way has worked every time for me (as well as several rescue organizations). You may have to modify it to work in adding veggies, but the basics remain the same.
My birds eat a base diet of pellets (non-colored or naturally colored), with additions of fruit and vegetables, some people food, and some cooked bird foods (Beak Appetit, Crazy Corn, etc), with the occasional bit of seed if I'm feeling generous.
And not a single one of them started on this diet.
Step One: Mental Preperation
First, you should understand that this conversion is not immediate and it will fail if you stop trying. It has taken me on average a month to switch, with benefits as we go along.
Second, find the tools at your disposal. There are several things that you can use as inbetween foods, or 'weaning' foods. Lafeber's Nutriberries and Avicakes are useful to get a little bit more nutrition into the bird and to convince them that food comes in different shapes. Both fresh foods and cooked mixes can be mixed with a small amount of seed to get a bird to try them and have immediate benefits. Birdy Bread can also be used as a 'weaning' food.
Third, make sure you're properly equipped. To do this right, you'll need at least two, possibly three food bowls in the cage. A clip on bowl that can be mounted higher than the usual food bowls is often helpful. A gram scale is an extremely useful thing to have during this as well.
Step Two: The Game Plan
One of the problems with sudden diet conversion is that the bird or birds stop eating. At no point do you want your bird to fear that there will be no food, nor do you want them to starve, obviously. This system works well for that.
There are three parts here. The old diet, the new diet, and any supplimentary things you want to add (such as veggies). The basic concept is simple. Your bird will receive their old diet twice a day for a specified amount of time, as much as they want to eat of it. The new diet (if they are non perishable foods) is left in the cage constantly, and suppliments are added when the birds are most likely to eat them (first thing in the morning is good). Once the bird is consistently eating some of the new diet, you cut down the time the old diet is available until you get to the point that they don't get any at all.
Step Three: Putting things into play.
I'll use some examples of how I transitioned my birds.
Two Green Cheek Conures, weaned onto a diet of seed and some fruit/vegetables.
Each of them had pellets available constantly. They received seed for an hour in the morning and evening to start, as well as avicakes and nutriberries in a treat dish, as well as fresh foods whenever I managed to give it to them (either morning or evening). Once they were eating the avicakes and nutriberries, I cut out one seed meal, and left it at that. It took almost a week before they even touched a pellet. Once they began actually eating the pellets, I cut their seed meal down to 45 minutes. Then 30. Then 15. Then, I closely monitored their weight when they were receiving no seed, and cut back the nutriberries and avicakes to treats only. Once that was completed, I declared victory.
One extremely stubborn African Grey who wanted to eat nothing but safflower seed and perhaps a pea every once in a while.
He took the longest, but was the simplest of all of them.
We started by offering him pellets constantly, and doing two seed meals a day. Unlike the green cheeks, he refused to so much as consider touching the nutriberries or avicakes, so I went to other options. He loves one flavor of Beak Appetit (after spitting out several others), and so he got that every morning while we were weaning him off seed in place of his seed meal. He also enjoyed pellets soaked in juice, and got those from our hand as treats. Eventually, he decided to attempt eating the pellets, and slowly weaned himself over. At that point, I cut down his seed, and now he happily muches pellets all day (and curses me if the ones he likes aren't in his bowl).
We also converted a sun conure from the rainbow Kaytee pellets to non-artifically colored ones in the same way, but that was almost trivially easy compared to the rest.
I cannot say that this will work for every bird out there, but the logic behind it seems very reasonable to me. The birds never go hungry, never starve, and always have their food available, they're just coaxed to try other things.
I hope this might help someone else out there getting through a conversion. Just remember, no matter how de-moralizing it seems, the bird will eventually try the new stuff. It just might take a very long time. And the glow of health of a bird on a better diet is worth it.