Update: First suggestions (and my own comments):
Done a bit more thinkin' about doors/popholes. I reckon going in through the concentric sections the same way the birds move out minimises the amount of gates required. I would have my own door into the coop while the birds could move in and out through the greenhouse via popholes. That would require a removeable bent wire tunnel of sorts during times when the birds could do damage to plants in the greenhouse.
a. Thought of strawbale construction [?], and render it. Cheap, great thermal qualities, excellent soundproofing and easy. What you lose in floorspace [this is not a priority in this design] Would quite happily hold up a light roof.
b. Divide this into 2 and it would be better bird management. Ducks on one side with access to current garden[s] and chickens on other side with access to fallow side.
c. Put it on an outside fence - walking thru a garden get to be a pain and it means external gates all over the place and these are all possible places of escape or entry by foxes, dogs etc
d. Consider dispensing entirely with a straw yard.
e. Make sure you can get a wheelbarrow thru the door[s].
f. I would run a deep litter system in your climate.
g. Remember the soundproof quality of mud brick - ducks can be bloody noisy at times.
I always tossed any ''straw'', including prunings etc onto the fallow side and let the chooks scratch the whole lot round for the season. At the end of the season I seperated the sticks out of the mulch and burned them in situ. This is your next garden.
1.Ducks will eat slugs and runners are successful at this BUT you have to control their diet. It is a maintenance diet only of grass and low protein feed. You need for them to hunt the slugs chasing protein and not be feed a protein type diet and have them dining on your vegies. When I ran this style of system I used to cut grass, chaff for the ducks [never feed them anything you might grow] and fed them barley. [Oats may also be useful for this.] Ducks are not fond of barley but will eat it. If you successfully nail your slugs....... and this should happen within a week... You can reduce the amount of time outside and increase their feed. BE CAREFUL.. ducks will eat seedlings not all the time and not every time. It is a matter of balance.. Ducks are also clumsy and will stomp on them too.. I would not give them any layer type food whilst they are wanted for slug control. Remember, I am in australia and Irish ducks might love the local barley but you understand what I am on about. If you let the ducks out and they starting biting at anything - throw them some food.... FAST.
2. Keep a spray container with a mix of hot chilli. Spray your fenceline and even under your plants with that. It will burn tiny seedlings. Also spray any likely hiding places with bleach, vinegar or eucalyptus oil. You want the fumes to dislodge them and get them moving. Chose whichever substance fits your wallet or standards. You are trying to keep them out or at least somewhere the ducks can find them.
If you are using the same housing for ducks and chooks. Put a large shelf on the back wall with a chicken watering system, external access to chicken nests for egg collection. Ducks cannot jump and live on the floor. It makes it easy to deal with chickens and if you must put them together you can feed them seperately. I dont think you can house them together and have them doing different jobs around the garden for you without creating a management nightmare. I did have my ducks originally exiting thru a PVC pipe with a bend in it but invariably a chook would work this out and go for the vegies. Put your perches higher than your shelf, plenty of them and at the OTHER end. The ducks will most likely sleep under the shelf end. Don't bother with duck nests at ground level they wont use them. You will find them all over the place, they will also lay at any time of day.
Chickens or chooks are best managed where you have clean hassle-free access to the eggs, food and water. If you ignore anything else I write do not build a chickencoop that you have to enter all the time to attend to these 3 issues. Go to the trouble of making sure you have outside [reach in] access to their water, food and eggs. These are your fallow garden workhorses and egg producers. They will also brood your duck eggs. [Ducks will lay anywhere except in a nest especially Runners]. Any food/garden scraps are just thrown over the fence into their run. Once a week or so, just rake over the fallow side. Mostly it will have old cabbages or whatever still happily growing. The chooks will eat most of this. Knock the last of it down and you can even throw a bale of hay in there for entertainment.
You can do a lot to minimise slug intrusion by removing any habitat, mow the grass around the edge of the pen very short....... make it at least a 2 metre strip. Set up traps for them along the fenceline and check daily. Once you have the garden 'safe'..... let the ducks out and get them eating slugs on the way in and before they reach the garden. I did wash the slugs off the pots into a sealed bucket and let them die [in the heat of australia]. Eventually I mixed this up and sprayed it around. Garden myth says this is a good thing to do. I have no idea if it worked because the slugs had all but gone by then and I had no way of quantifying it.
You can also string a light up in your veggie garden. Ducks work quite happily at night with a bit of assistance. They dont need much light.
Your fence should be a minimum of 6' high. Both ducks and chooks can and will fly over that height if frightened. Once they learn they can clear it - there will always be 1 or 2 that will. Also when chooks go broody they will want to fly out. Any lower than 6' and you are courting problems.
I would not make a pen out of chain link. It is overkill but then again, I am in australia with a variety of light wires available so I cannot make an Irish suggestion here.
I made my fences super tight at the bottom and floppier at the top so that chooks dont learn to run and flap up them. It also discourages foxes and cats from climbing them. Foxes are excellent climbers and love ducks. Just lean your fences inward a few degrees. I stay my fences at 45degrees and use the stays to grow cucurbits up and the rest of the fenceline for peas and beans, nothing too heavy.
I use 2 metre wire octagon shaped with about 50mm holes [yes baby chickens can escape] with a strained wire at ground level and another at about 400mm to stop foxes pulling at it. The top wire was at 185mm not strained, basically the wire was just straightened out neatly...with the top 150mm flopped outwards. I cut the mesh at the corners to facilitate this.
I have never had a hothouse but one on the outside end that you have your shelves and nests would be ok. Easier to find you way through a hothouse than an overgrown and probably wet garden. Attached to the end of a strawbale fowlhouse would assist its thermal qualities, you would soon find a balance with a thermometer.
This is based on an annual garden. Perennials can be included but again they are managed differently. I would find 2 pens to be entirely adequate but I am not in Ireland but I do live where there is one major growing season. You mentioned 4 or 5 gardens - what for? The amount of fowl you need will be determined by the size of your veggie plot.
This system minimises external inputs for food too. I always grow rocket for chooks and they get anything that isnt suitable for human consumption. The chook house and fallow garden provide nearly all of the mulch you need for your new garden. This system should be excellent after about 3 seasons. You may wish to try a cover crop when you first start up. I have started for myself and others a number of similar designs...... generally I put all the birds into one side and on the other I start with a cover crop. I use a packet of parrot seed as a great starter crop. It has a variety of grains and is an interesting mix, you can also assess soil quality etc. Once the birds have one side clean, I move them over and they can play in the other crop for a few months.
I note your octagon. I only ever built squarish and I have no defence or reason.... Laziness maybe but isnt that the underlying principle of Permaculture?
Mike, the underlying reason is this: Much less material is needed to enclose a given circular area than a rectangular or square area of the same size. An octagon is simply an approximation to a circle. A circle is difficult to fence. I quote from an article on the efficieny of round barns:
"The Illinois authorities have conducted innumerable tests pertaining to the efficiency of the round barn; they have built two of
these barns on the grounds of the college farm, and for several years have utilized them with great success as quarters for live
stock and to provide storage room for grain and hay. The results of their detailed investigations show that the circular structure
is much stronger; that the rectangular form requires twenty-two percent more wall and foundation to enclose the same space;
and that the cost of material is from thirty-four to fifty-eight per cent more for the rectangular building. The round barn offers
greater convenience in storing, handling and distributing the feed while much greater strength is secured with less lumber than is
possible in the case of the rectangular building.".
Similarly, comparing a cube and an octagonal prism of equal radius and height, the octagonal prism gives me c. 130% of the ground area and volume of the cube at only 110% of above ground surfaces (=walls and roof). Construction is, however, more demanding...
Thank you, Larry, for your comments.
Of course I do have the chickens health in mind as well. They shall get
everything they need. I have a source of organic feed grain, which I get
for my goats, plus lots of whey for about 7-8 months a year from making
goats cheese. Grit and lime would also be provided, and food scraps etc.
Bran, mash etc. all is available. I'm not planning on feeding the birds
on that little bit of ground alone.
I'm also in the process of building a small mobile run, our last one
wasn't sturdy enough. However, in order to achieve sufficient control of
bugs/slugs I need a bigger set up than I can move on my own, especially
since I've been having a bad back since sweet 17. The small mobile run
will be a supplement for e.g. the soft-fruit garden. Such
'mini-tractors' are handy but I like giving the birds their 10m2 each
which is difficult with a mobile set-up.
I've toyed with the parallel bed kind of idea but the need for a
permanently grazed perimeter made me move towards the concentric idea.
Mark (in Wisconsin, USA) [my replies in italics]
Some more comments from Scott in Australia
From Fran in Australia come these words of wisdom: