Sorry, bit of a long story, I hope some of it is useful to you though!
If the seeds won't sprout at all, it could be they are poor quality or simply too old (just like old seeds for planting in your garden do not always sprout, even if the quality is/was good) It may also be that some kinds of seeds take longer to sprout. To be sure you could make a second batch (just for testing this, not necessarily to have your bird eat them) and see if some of the seeds do take longer to sprout than others. I haven't tried sprouting seeds yet myself, so no useful advice on that from me, but I did hear it takes most people a couple of tries to get it right.
When I got Puck, he was on an all-seed diet too. He was still very young (around 8 weeks I believe) and only just recently had started eating completely on his own. He was partially handfed because his parents refused to feed him anymore (it is illegal here to handfeed a bird unless it is to save it from starving if the parents won't feed it themselves) But since it is easier to make sure a bird doesn't get a shortage of nutrients with pellets, I did want to switch him to those.
At first I gave him two separate bowls:
- One bowl filled with seeds
It's a mixture for Lovebirds, not perfect but he loves it and it was the only one I could find at that time, that had no sunflower seeds in it.
- One filled with pellets
I currently still feed him this, they're Versele-Laga's NutriBird B14 pellets (for tiels, neophema's and lovebirds). But I checked and there's quite a lot of colouring in this food (and they smell reaaaaallly sweet) so I would recommend getting something else. I plan to switch Puck to a different pellet eventually, too.
He refused to try the pellets until I pretended to eat some myself. Still, he wouldn't eat much of it at all, maybe 3 pellets a day? So I decided to give him a 50/50 mixture of seed and pellets in a single bowl, and give him a measured amount of this mixture daily (making sure he'd get enough food even if he would refuse to eat the pellets in the mix).
Then I would give him a fresh batch of this every day, so I could see how much he ate of the pellets. To my surprise he did start eating more of the pellets then, although he still prefers the seeds.
Knowing that he will now definitely eat the pellets, I give him a fuller bowl, and just let him decide when he wants to eat his pellets and when he eats his seeds. I'll give him a fresh batch whenever he has somehow pooped in his bowl (he still sits in his bowl while eating sometimes) or when he has eaten so much of it that what is left isn't enough to feed him for an entire day (I have school during the daytime but the hours are irregular).
I think I'll continue to give him a 50/50 mix of seeds and pellets, as in my opinion eating seed is part of a bird's natural behaviour and as such should the bird be able to show this behaviour. Puck regularly gets fresh vegetables and fruit (we're still trying to figure out which ones he likes) so I don't worry about him not getting all the nutrients he needs with this food.
And yeah, he'll definitely try to eat anything I (pretend to) eat myself, as he was terrified of green beans when I got him, and now actually likes eating them, after he saw me eating them for dinner :P