No one answered? The white stuff sounds like ash and is normal. What you have right now can be used with nothing more done to it by next March. It probably did a lot of composting in the hen house if your bedding was in good proportion to your droppings. I run my henhouse like an indoor compost pile in the winter, and, yes, I do use some of it as I build my spring piles, but I primarily use it as a mulch.

You might just want to start building a pile now for your kitchen waste and look around for carbon sources other than your mostly composted chicken manure.

Your chicken manure is the fuel looking for something to "cook", not the other way around.

Most of us don't feel compost starter is a necessary addition to a compost pile, btw.

Yes, I agree. I spoke carelessly. I get it in the middle of my hottest piles. I have had piles burn my hand, but I've never had one ignite.

I agree with toxcrusadr that it is most likely some fungus, mold or actinomycetes. I have definitely had the characteristic white-ish looking stuff from actinomycetes on somewhat drier fibrous material like cardboard (which I'd say looks more like mycelia but can be a bit powdery). After a while, the cardboard would crumble easily in the hand, i.e. it was being decomposed thoroughly, and have a very distinctive earthy smell, more acute when damp. (I believe I read that actinomycetes are one of the sources of the chemical geosmin, which literally is 'earth smell.')

Some of the white stuff would look powdery especially after turning or disturbing the pile. (Note one shouldn't breathe dust etc from compost into lungs, esp if shaky immune system/immune compromised, but smelling carefully probably okay).

Anyway, whatever it is, almost certainly just a normal part of decomposition. Some fungi and other decomposers prefer damp/wet, some prefer dry, some hot, some cool, etc., so pretty normal to see some variation - conditions in the pile will also vary from layer to layer and further in/on surface.

All those denizens of the pile also have their own reproduction methods and ways to spread/move through the pile to the food and conditions they want, and that can make things look different.

Earth smell! Always wondered what that was.

https://en.wikipedia.org/wiki/Geosmin

Geeky environmental chemistry stuff. Cool!

I find it amazing how sensitive the human nose is to geosmin. Five parts per trillion???

Yes, amazing. Methyl mercaptan, which is used to odorize natural gas, has an odor threshold of about 1 ppb - that's 200 times more than 5 ppt.