Garden surprises

I planted a few packets of "cottage garden" seeds to colour things up a bit and attract the bees.  But I was puzzled when this massive plant popped up in a spot where I hadn't planted anything.  It grew like a triffid and it took me over a month to work out what it was.

All I can think of is that there are sunflower seeds in the chicken feed and occassionally a bird gets in the run for a quick meal. So perhaps one made a deposit as it headed out of the garden....