Just wanted to share one idea that worked for me to get your stubborn birdies to try some veggies. My parrotlet loves those kebab shredder toys, so I added one to my new parakeets cage as well. I also put it next to her favorite spot in the cage. I then started clipping different veggies to the kebab and surprise, it worked I think once most birds get a taste of veggies they will most likely love them, it's just getting them to take that first nibble Anyway, now Freckles will eat anything I put there!
Also the Kebab toys are a lot of fun to shred and maybe while they are shredding them, oops got a piece of veggie, lol!