feathers

just noticed today that some of the girls tail feather are starting to look a bit thin (a bit like a cartoon fish skeleton) do I have anything to worry about or are they getting ready to moult. the girls are about 18 months and did not moult last year

You know, Foxy - a fish head and then a line with little diagonal spikes coming off it, just like Tom & Jerry 

Sounds to me like a moult - those feathers seem to be worn out. But if they're moulting the feathers will also fall.

Apparently they appreciate a little Poultry Spice when they are in moult, and apple cider vinegar in their water if you don't already do it. Helps them to recover quickly.