Hi - Greetings from Scotland.
Well, their staple diet here is HAGGIS - no, seriously I am joking.
We have kept hens for many years and each day they get Layers Pellets, mixed grain (some say this makes them fat - has not done so to our hens). We also give them loads of food scraps,
avoid white bread - no good and a high salt content. Our hens get pretty much everything. They adore blueberries, cheese (only a small amount), they go crazy for spaghetti Bolognese leftovers,
raw minced beef etc. They are not particularly keen on cucumber/tomatoes but love apples and bananas.
No Avocados, no apple seeds.~~No white potatoes - cooked or raw, skins or flesh. These are toxic to hens. And no onions.
Hope this helps a little. Good luck with your new hens.
p.s - what breed of hens are you getting?
Don't waste the Haggis on chickens. Bobby Burns didn't write a poem about laying mash.
Avocados: I've seen several posts here from people reporting that they've heard/read that Avocados are harmful to chickens. I've also seen several posts from people who said they have, often repeatedly, fed Avocado to their chickens with no ill affect. What I have never seen is a post from someone who said the fed Avocado to their chickens resulting in a bad outcome. Make of that what you will but be advised there's a lot of misinformation on this board.
In a recent post in this thread someone said 1-they don't feed their chickens meat, & 2-they try to feed them as naturally as possible. Which is it? Chickens are omnivors. Meat is a natural part of their diet. I've seen mine eat mice, snakes & baby wild birds. Much of the misinformation here comes from "experts" who have 4 chickens in their backyard & they've had them for 6 months total.
Be aware that what's poison for people may not be poison for chickens. Tomato plants & Rhubarb leaves come to mind. Toxic to humans but I;ve seen chickens eat both. Also what's toxic to dogs may not be harmful to chickens. Grapes are an obvious example. Toxic to some dogs but my chichens clear any grapes they can reach off my grape vines.
Basically, they can eat what you can eat. We clean out the fridge once a week &b all the leftovers go to one pen or another. They get very excited when they see the big silver bowl.
People say chipos or crackers are too salty for chickens, For their complete diet they are but who plans to feed their chickens on crackers? If you have a part of a box of crackers that goes stale go ahead & feed them. It won't hurt a thing. Same is true of sweets. Got a couple pieces of left over birthday cake? Trrow it in their. Switch your chickens to an all cake diet? Don't be silly.
Use some common sense-which actually isn't all that common.
ETA_ I love Haggis! I never have any left over.
ETA2-I see references to "fodder" showing up here recently. The associated descriptions seem to indicate the people are talking about sprouted grains. That's not what fodder is. A dictionary is a useful tool.