Another moulting question.?

[muckman]

Hi all, I have had 6 black rocks since october I got them p.o.l and they soon started laying.
The thing is 4 of them are loosing fethers from the vent area and the top of the leg ,Iv looked and checked the area and they seem very clean with no mites or fleas.
Is it normal for them to moult in such a short time? With what iv read on the net it says they moult in autumn
Thanks Muckman.