as with this one I have noticed on other recent posts of Blue Tits they seem to look a little bit scraggy at the moment.
Yes, I had a real scruffy one turn up on the feeder the other day and was wondering what it had been up to. They've been looking very sleek and tidy all winter but definitely a few more raggy ones now.
Perhaps a pre-breeding partial moult or something ? It won't be long until they're pairing up and nesting.