aluz and shaz128blue have offered you excellent advice.
In addition, I would suggest you keep a close eye on how they respond to the toy that looks like a bird.
You may want to put it outside the cage on a play area and limit the time your budgies spend with it.
Many budgies will become obsessed with the parakeet toy and end up spending their time trying to feed an mate with it. Some even become aggressive if you approach them when they are with the toy.