To keep the grass under control in a small plat (cobnut orchard), I strongly advocate ducks instead of sheep. My plat is about 0.05 hectare (1/8 acre) and 14 ducks keep the vegetation down beautifully, although I am not sure if they eat it or trample it under foot. I scatter a daily half scoop of layers pellets or mixed corn wherever the grass or nettles need attention, but one could equally well use a mobile pheasant feeder. A small pool for bathing and drinking and a shed to shut them into at night are also necessary. The eggs are a bonus too.
Any breed will do the job: I started with Aylesbury's because they are supposed to eat grass. Unfortunately a fox ate them. I enclosed the plat with electric fencing and tried Khaki Campbells, but when I had 'flu and failed to shut them in for a few nights the fox ate them too. I am more careful now and so far it has paid off – or else the fox doesn't fancy cheap mongrel ducks. I suspect four or five geese would eat more grass and need less feed, but I have been warned that they might strip the trees of all leaves and tender shoots to a height of just over lm (3ft3in). But that is nothing to the damage my Hebridean sheep would do to my cherished young cobnuts; they recently jumped out of a field and killed an ash tree which was over 2m (6ft6in) in diameter by ring-barking its trunk.
For more information on cobnuts see the Kentish Cobnut Association.