Small birds are suffering during hard winters. Their weakened body can catch e.g. salmonella which is spreading via contaminated seeds and untidy feeding sites like these Blue Tits.
Fluffy feathers are a typical symptom of salmonella. Also these birds might be too weak to fly away.
I'm not sure about the twisted head, but I assume that is also due to salmonella.
This Blue Tit has lost the feathers from the right side of it's head. I first noticed the odd coloring of the head ...
... and then I got the picture which shows clearly what was was the problem.
Some birds have deformed legs, but are still able to cope somehow. This Blue Tit was not able to use its left leg. To keep the balance it was leaning to the right. From the front ...
... and the back view.
Sometimes the birds look like beaten. This Coal tit has lost it's right eye.
This Great tit has lost all feathers in its neck, the bare red skin is visible. I don't know if these are due to salmonella or are the birds been attacked (or both).
And yes, we are cleaning our feeding site to prevent salmonella spreading further.
