Ted, I planted (overseeded...no till whatsoever) last January with wheat, rye and ryegrass as well as clover and brassicas and got good germination. Granted it took longer to get a green field but it did well.
It is for a different purpose, but I've seen wheat, grain rye and either crimson or arrowleaf clover no tilled in pasture for winter forage as late as the end of October. It sprouted and came up and I shot deer eating it.
Most farmers haven't even cut their last cut of hay and as a general rule don't drill until that is done. In the lowcountry they haven't even harvested soybeans so it will be a while for them as well before planting winter wheat.
Owing to a lazy streak, and our experience with summer grasses coming back and crowding a plot, we rarely plant before now and often do it in phases where some is as late as mid-late october.
When I was a kid our club planted during the middle of bow season which back then was early October.
With the seasons opening earlier, It seems everyone is planting earlier than ever before.
Mix collard seeds in with wheat and oats or abruzzi rye and watch what they eat first. Don't know the nutritional values of collards but deer love them.