Feather Stumps

When checking my light sussex today I discovered that she had quite a few feather stumps on her, as in just half a quill coming out, without any 'feather' on it, I cant find anything about it on the internet, and wondering if it is a problem? It is usually her feathers that i see on the floor more than my other bird as well.

Even though she's already got feathers?? I thought new feathers just came after the moult? Or am i really a true novice?

Can't seem to see many feathers in the coop, apart from the odd fluffy one. I suppose my biggest concern was whether this was indicative of any real problem like louse etc?