Considering sowing a few Kale in September

I'd never had problems with pigeons eating the kale until last winter when they pecked the lot to stumps.  I could have lifted and tossed the plants into the compost bin but instead covered with fleece - as well as protecting them from the pigeons, despite a long and cold spring the kale picked up and provided lovely tender leaves.  So it might be worth fleecing them to encourage growth especially as we seem to be getting a rather early autumn chill this year.