What's the earliest time of year you can hatch out chicks?

[DaisyMooSteiner]

Our naughty cockerel is going to have to go asap after he went for one of the neighbours' kids, but we were hoping to hatch out some of 'his' eggs before he goes. Is it too early now - should we wait until the weather gets a bit warmer? They will go in an incubator if that makes any difference.

I know people who are doing it already but I think its too early really. If you have the space to keep them inside for longer its not too bad.