There is a possibility that she is just tired during her moult, also, she (I think it's called this) could have either Marek's Disease or Newcastle disease, either way, I think you need to ask a specialist for advice unless she has stopped doing it now

Chickens Generally do not need much space. A small " ark " is sometimes sufficient for 4. On average, 1m2 per chicken is ok. If you got an eglu or something, you can keep up to four chickens in the smallest of spaces. Enjoy your chicken keeping.