If your birds continue to sleep on the floor, they will most likely be scalded from laying in their own urine, causing feather loss and irritated skin. It can also lead to respiratory problems from sleeping too close to the bedding. These are both issues you need to be proactive about sooner rather than later. There is a myriad ways you can make a roost that your birds may enjoy. It seems like you have been offering them metal options, which are slippery and ungrippable for them. Try offering a wooden roost, any way you can figure it out, it is not rocket science.