Just an odd suggestion that might go against everything we have commonly been taught about sanitation. You might consider not throwing out the old bedding every day. In the wild the bedding gets all kinds of nasty, attracts insects and grows nasty bacteria and mold. A couple of reasons that is actually a good thing. Firstly the moisture from the droppings allow humidity buildup which is actually good for healthy skin, feather growth and hydration. Secondly, baby birds do a lot of immune development prior to fledging. Their body is basically sampling bacteria in the environment and building up antibodies to those things. I've rarely cleaned nest boxes for my birds unless they started to stink so bad it was bothering me and I've never had a sick baby because if it and rarely have sick adults. Also I do think we over sanitize and it has the potential to lead to a depressed immune system. I don't think we need to let things get nasty and full of mold, but I also don't think we are necessarily helping by keeping things super clean. With just a single chick in the nestbox, you can probably go a few days plus without having to worry about nestbox sanitation. In fact, chances are very good you could leave that baby in the box the whole time and never change out the old bedding until after she fledges. Especially with a mom that likes to throw stuff out anyway. However, I do recognize that moderation and basic sanitation when you can achieve it without bothering the parents is a good thing.