Pets are out of the question in our particular self-sustainability scenario with one singular exception (see later). Dogs and cats are carnivores and would add a significant burden on the need to produce animal protein. A working barn cat would be useful by keeping down the voles and mice, etc., a bit, so that option might be worth the hassle of having to increase the rabbit production a little, but on a small plot like this, the cat would spend most of its time somewhere else anyway (speaking from experience). So IMO not worth it.

But I do count on having five egg-laying hens in our scenario, producing about 1000 eggs a year. And those could also be pets. A friend of mine has bought retired egg-laying hens, with the intention of having them lay eggs for a year and then killing them for meat. His wife took to observing them after work (first mistake), started to recognize their individual traits (second mistake), and gave them names (third mistake). At that point, she became opposed to the idea of killing and eating them, so they were allowed to live until natural death. And AFAIK, they continue to do this still, about ten years later. The hens still provide them with eggs, and they live comfortable and happy lives until death. They are not cuddly like cats or dogs, but they can get affectionate and entertaining.

From spring to fall, five hens should be able to find enough food in the coppice, with occasional supplementation with kitchen scraps. Hens can and will eat virtually anything, although they prefer insects and small animals. In the winter, they would require feeding, but it should be possible to grow enough surplus to keep them alive through winter with a combination of food scraps, cracked grain, and boiled potatoes/potato peels (there will inevitably be some potatoes that are not fit for human consumption due to pest damage) mixed with shredded and boiled alfalfa hay. It is also not unreasonable to expect more walnuts than one person can comfortably eat, and hens will love those in winter.

Rabbits or guinea pigs would not be pets in this scenario; they would be meat. Their whole purpose would be to eat plant parts inedible to humans and convert them into something edible. They can be omitted entirely in favor of pet hens, but the plot will thus inevitably lose some efficiency by using all excess plant material (and there would be plenty) just for composting.

Like the hens, the rabbits should be able to graze in the coppice throughout the summer with the chickens, since they eat different stuff. The water cleaning facility, the fallow field, the coppice, and the orchard should provide enough plant material to make hay for winter to keep one buck and two does alive through winter. In the spring and summer, there should be enough surplus plant matter to get at least 10 kg of meat out of their offspring.

With rabbits, there would be a need for outward input – vaccination. Without it, a deadly outbreak of myxomatosis is inevitable at some point, again, speaking from experience.

10 kg of meat and 1000 eggs would provide about 90 Mcal, getting the total to 954 Mcal, enough to keep an active person alive.

Pests are another problem. The hens would help a bit with pest control by devouring any insects that travel through the coppice. But mice, rats, and voles would be a problem. Hens will kill a vole or mice if they catch them, but they are not particularly good at catching them. In my opinion, the best self-sustainable way to keep these pests under control would be to strategically put bucket traps baited with walnuts. And subsequently killing all captured rodents and feeding them to the hens.

What slugs and bugs get onto the veggies anyway can be in part destroyed manually, and in part by homemade insecticides. For that purpose, growing a few potted chrysanthemums would be necessary to make an insecticide spray if needed. Daisies growing anywhere in the garden should be cherished, because they can serve in this capacity, too.

To someone uncomfortable with killing animals of any kind and in any context and for whatever purpose, I do not recommend attempting food self-sustainability. Whatever spiritual connection one feels to fellow living creatures, that connection is inevitably strained beyond breaking point when said creatures literally threaten one’s survival by destroying their only food source. It is easy to be high-minded about this when the food comes from the supermarket. It is less easy when it comes from hard work and a yearly gamble with nature.