Foxproofing isn't that difficult. You would need a covered and secured run so that they could be out during the day. Place their coop inside this run. dh has concreted ours all around so that rats/foxes can't dig underneath. Make sure there's no holes or gaps and that the wiring is good quality and not flimsy.
They need to be let out of their coop each morning. Fresh food and water every day and I sweep up the mess last thing. I hose down and sprinkle disinfectant down. They do produce large amounts of poo. If you keep on top of it it's not smelly. We get pet sitters in to come and see to ours if we go away. Don't expect relatives or friends to come and do it unless they're chicken fanatics. The mess will put any 'delicate' people off and your hens won't be cared for properly.
I got my chickens from breeders, but you need to be careful which ones you buy from as four of mine came diseased. Two died, one I restored to full health, but she's never been a good layer and the last one I still have, but she's knackered and doesn't lay properly.
A decent breeder doesn't have dozens of hens all mixed in together. Their environment should be clean and well organised. Don't buy from anybody who seems like they're a sloppy joe. Always choose the hens that are hardest to catch 
If you get something like a hybrid, they have more resistance to disease and are good layers. Pure breeds are a bit weaker and might not lay so well. I find Light Sussex are a good breed - make great pets, are intelligent, funny, cheeky and good layers. Mine come into the house and nick the cat's food 
If you get a hybrid, you'll end up with an egg a day from each hen.
Feed a base diet of layers pellets and mixed corn as a treat. I also feed mine kitchen scraps and they love cooked sweetcorn, spring greens, couscous with sultanas and pasta. Don't give them junk food or anything that's salty. Mine love unsalted homemade curry 
You need to worm them every month - I use a product called Flubenvet - you just sprinkle it on their food each day for a week. You can still eat the eggs. Do that every 4-6 weeks, esp. through the warm weather when the soil will have worm eggs in.
You will need to remove the top few inches of soil about twice a year and sprinkle garden lime down to keep it sweet. I have several concrete flags down as things will get muddy in the rain if you just have soil. Chickens dig everything up and rake the grass up too, so be careful if you intend to let them into the garden. They're quite messy and don't care about your plants.
External lice can be killed with Ivermectin. Never use the powders that are on sale for chicken mites/lice. They don't work. You have a 10 day egg withdrawal period if you use Ivermectin. I only use that twice a year.
I bed mine down on newspaper and just remove the top few layers each morning. In the cold winters I add some straw. Never use hay as it can contain mould which will cause respiratory problems. Birds need good ventilation and can withstand cold, but not damp or wet.
If you keep them purely for eggs then you must realise that they only lay for the first few years of their life and after that you may want to keep them as pets - but you won't get eggs from them - or find someone who'll wring their necks for you. Only one of mine lays now, but we don't eat many eggs, so I'm not bothered.
Vets generally don't know anything about chickens and will either shrug and look worried or might know somebody they can phone for advice (my vet does that). If chickens become sick they tend to go downhill quite rapidly. The main killers are debilitation from parasites and infection. If you give them a good diet and keep them clean with regular worming they should be okay.
Troublesome behaviour can include - being noisy, trying to escape, bullying their friends - the fewer hens you have, the less likely this is to occur - and eating their own eggs. I've never found any to be aggressive and they're very tolerant of humans. They don't tend to like being picked up and cuddled unless you've had them from being very young. They look at you like you're mad, but will listen very carefully to anything you have to say and will never tell a living soul Great company when you're gardening.
Chickens have great personalities and are a lot of fun to have around. You should get 4 if you have room. If you were to get 3 and one died, you wouldn't be able to introduce a lone hen as the others will probably pick on it. If you were to end up with three, you'd have to get two to even things up a bit. Birds are very unforgiving with each other and will bully and peck in order to exert their authority over a weaker one.