Personally I always kept the food, grit & water indoors, because then
a) it keeps the rain out of the food (and wet food goes off very quickly, and can't be fed to them for fear of causing health problems)
b) they have access 24/7. Hens need constant access to water. This is particularly true in summer when the heat rises, sun comes up far earlier than you want to get up and let them out in the morning, and egg production rises. A lack of water (even one episode of dehydration) can permanently reduce egg production. They also like food early in the morning - if you feel their crop in the morning, it's completely empty (if it isn't, and feels like there's a hard lump in there, google impacted crop - it's easy to treat yourself, but can be serious if you don't treat it) which means they're rather hungry.
c) It keeps the rats out at night. Rat's aren't attracted to chickens, they're attracted to sources of food.
And in all fairness, I never found any reason not to keep the food and water inside.
If she's kicking the food over, then I'd suggest buying one of these sorts of feeders, and hanging the feeder (at the same height as her back; this will also stop her flicking food out with her beak, a wasteful habit known as 'billing out') if possible. Even if that's not possible, it will be more stable than a bowl (I'm surprised the the bowl ever avoids being knocked over tbh!)
When I say porridge, I do mean actual porridge oats! Sainsburys Basics (only the best for my girls . . .), mixed with water or bio-live yoghurt, and warmed in the microwave. Although they may be a little suspicious at first, once they taste it they'll love it. To make it possible to eat, it needs to be made quite stiffly (so that you can form peaks with it IYSWIM). This can, however, have the unfortunate side effect of them eating it too fast, getting it all stuck to their beaks, and then managing to flick it across the coop, pebbledashing the walls with porridge! I digress, however . . . I have used it particularly for any supplements and potions from the feed store that are meant to be good for them.
The most accurate dosing method for oral liquid medicine (unless it needs to be injected, your vet should be able to give it to you in this format; don't start messing around with powdered medicines where dosage needs to be accurate) is via a needle-less syringe. There's a bit of a trick to getting it down their gullet - you need to kneel, chicken between legs, use your inside thighs to restrain the wings (firm so she can't wriggle but without crushing!), your backside to make her bend her knees slightly, your left hand to prise open the beak (thumb to stop her moving her head back, one finger between the upper and lower mandibles), and your right hand to operate the syringe (there's only one hole that it'll go down, it's big enough to fit a mouse down (yes chickens have been known to eat mice whole!), so it's obvious where it is; you won't suffocate her).
For greens, they don't have to be human food. Strictly speaking, it's illegal to feed anything to livestock that has seen the inside of a kitchen, but that's another story. Half an apple is an awful lot of food for one chicken, and it's not nutritionally balanced, as layers pellets are. You can also opt for things like grass (make sure it's short, to avoid impacted crop), anything from your veggie patch that has been 'got at' by slugs / insects, fruit that's a bit over-ripe, mine always liked lemon balm - someone else had planted the herb, I never worked out what to do with it but they ate it quite happily! If you can, just letting her out for a wander will have the desired effect in terms of the intake of greens - she'll graze on whatever takes her fancy.
There's a thread on introducing chickens on here from the last few days. If you haven't already, then have a read through as it's quite helpful.