Blackbird's open mouth (1 Viewer)

Our garden is full of birds. One young blackbird has it's mouth permantly open, heartbreaking to watch her try to get one of the currants I put on the kitchen windowsill just to watch them fall off. Have tried a few things, but just in case anyone has the same problem, what has worked, is a small jar (like a spice/herb jar) filled to the top,with currants and warm water to soften. Then I prodded them in the har to make them stick together and lay the jar on its side in the windowsill wedging it in place with the slightly open window. While still a chore for the wee soul it does now manage to get a few. Keeping my fingers crossed the beak may eventually close. It has access to water so is drinking from a small pond. I'm pretty sure she knows I'm trying to help as I can get as close as a couple of feet from her, talking softly. According to thr RSPB it's probably gape worm.

I read somewhere that gape worm makes a bird lose it's appetite so if it is feeding and drinking then maybe it's something else?

How's this bird doing?