I think you will be ok with the geese joining the ducks. If it were the other way around …the geese may not accept them.I have had runners and geese with no major problems. I housed them in a large packing crate I scrounged from a local aircraft plant. It is 8×5 and 5 feet high.I cut a door and window in it with a chainsaw, hinged the door and put chicken wire over the window to keep out predators.I also hinged the lid so I could get inside to clean it out.In the winter, I screw a piece of wood over the window to keep out the cold. As far as the ducks not laying…ducks are like that. They won’t lay as consistantly as chickens. They are also messy and not too concerned where they lay. I have even found eggs in the bottom of the plastic pool I provided for them to swim and play in.They may also not be getting enough protein…I give a little grain in the morning and let them free range at will in a huge lot that is fenced.You might check around where they play and run and see if you can find some eggs. You never know.
I have an acre smallholding which is mostly for fruit and veg growing but there is also an orchard area and some »spare’ (!) grass area. We have a small movable arc with 6 hens which do a lot of grass cutting but they mostly stay inside the run to keep off my veg. This leaves an area of about 20mx15m of grass that needs cutting. I would dearly love some ducks in a moveable run on this area but… have a few questions first… 1.. I live next to a river so would they disappear off with the local mallards or could they be trained to return for some grub and to be shut into a run at night? A local whistles the mallards for sliced white and they come flying in from miles around! 2.. Could they be let out at 10am to free range or would they devour my veg in the same way that chickens do? – many things are fenced off against the pigeons anyway. 3.. Do they eat grass anyway or should I be thinking about geese? Any help and advise would be gratefully received. Perhaps it should be mentioned that I am vegetarian so not too keen on the idea of goats etc.