Some pet animals, birds included, have forgotten
how to have fun with things (many humans have too).
You need to build interest in the toys and to teach Maddie how to play with them.
When you know Maddie is watching you, start out by examining one or 2 toys yourself. Look each of them over. Reach out & start to carefully manipulate/rotate the toys.
Smile often.
Talk softly, but with building excitement as you do so. Use your bird's name. Slowly play with the toy yourself while describing how much fun you're having.
Mention "out loud to yourself" how you think Maddie will enjoy it when she's playing with it.
If there are certain motions that you know Maddie likes to do, demonstrate that the toys does that. If the toy has destroyable bits (paper, cardboard etc.,) destroy some yourself. (It may seem boring
but just think of it as popping bubble wrap).
If Maddie comes over to watch, make sure she can clearly see what you are doing. After a few mins, take the toy you're playing with and carefully set it down between you and her. Pick up the other toy and repeat the *OIP* that you were doing with the first toy. *Observe, Investigate, Play*
If Maddie comes forward to check out the toy, give her praise & encouragement. If she picks it up to check it over, give her more praise & encouragement.
It may take a little bit, but Maddie should get the idea and start to investigate the toys & play with them herself.