Need ideas on how to supplement feed.

I feed primarily Nutrena Naturewise All Flock. It is about the same price as what you buy, so I feel your pain.

One thing I do is cut my feed with some rolled oats. The feed is 18% protein, so it doesn't hurt to add some oats. I add about 2-1/2 lb of oats per 40 lb bag of feed. It's not really a huge savings, but I like to do it because both my chickens and ducks love the oats. I also add in a couple of handfuls of homegrown black oil sunflower seeds. I cut back on the pricier add-ins I used to use (brewer's yeast and omega-3 supplement).

My chickens also get table scraps. Since I have a large family, it adds up to quite a bit of food, but if you spread it out over 16 chickens, it doesn't end up becoming a nutritional problem.

Probably the best thing I do to reduce feed costs is grow my own forage. I grow wheat grass, which is a very cheap and easy endeavor. This thread gives some good information: https://www.backyardchickens.com/t/713334/growing-fodder-for-chickens

 

Part of what you need to consider is the protein content of the feed that you are giving. Dumor has several types of feed with different protein %. You want to be around 16-18% depending on the age of your birds and whether they are laying, molting etc.

I feed a 22% layer ration that I cut with a 13% 9-way scratch. I also grow wheat fodder for my birds. I started for the geese but the ducks and chickens also enjoy it. It is easy and inexpensive though takes up a little bit of space. The link provided has alot of great info. I pay $13 for 50lbs of wheat. I use only 2 cups of grain and get about 4-6 lbs of fodder.

 

I do fermented feed for my ducks and geese and they are looking better on it. I am fermenting the same pellets that I would be feeding anyway so that part is the same. There are several benefits of the ff. One is them eating less as its more digestible, a second is the poop doesn't stink. The reason that the stuff is so great is that the fermenting is a probiotic, sort of a predigest of the feed and it ups the protein content of the feed by somewhere between 8 to 12 percent. I cut mine with grass pellets (less then $10 for 50lbs but could also use oats) to reduce the protein and the cost even further. Anyway there is a very long post in the meat birds section but the thread is now about all types of birds including layers, pets, ducks, turkeys and whatever else anyone has and would like to feed the fermented feed too. Here is a link if your interested. Just to note I have layer ducks not meat ducks and have been doing this for them since mid September. I noticed that the smell from their poo stopped smelling in about 5 days. I can honestly say that my 15 ducks now smell less then the 5 ducks I had a year ago. It is hard to say how much less they eat with the ff but they do eat less on it. Most people are finding a reduction of feed cost even if they are feeding the same feed but fermented.

 

There are a few things you can do than buy top shelf feed for your ducks and chickens. First off I assume you pen your flocks up, as I rarely feed my free-ranging chickens as they prefer to find their own food & will only eat out of the feed bowls if they happen to wander by them. I feed my penned up hens Hubbard's Layer Feed and supplement it with table scraps. I pay $12 a 50 lb bag, but I also buy from another breeder, who buys in bulk. Now I do put out 2 bowls of feed for them in the morning and I mix in water with it, making a porridge out of it. Otherwise the ducks will carry dry feed to their water bowl to moisten it, and waste a lot of food. Plus dry feed tends to block their nasal passages which they blow out at the water bowl. But after they fill their craw, then tend to want to find a mud puddle to root around for worms, bugs, grubs, and roots for the rest of their nutrition.
Second, if you have the means, you can find a local farmer who makes his own poultry feed, and contact them for prices, which is always cheaper than what you will find in the feed stores. Where I am located, the Amish make a Chicken mash, for $20 per hundred pounds, and it is exactly the same stuff they feed their own flocks. The Ducks will eat it, but don't like it as much as they like the processed crumble, which is ok, as they will just forage more, (I think it has to do with Texture, more than taste).
Third, if you have the means, you can find a local mill that will grind you what you want. In the fall, you can bring in a ton of shell corn and a ton of alfalfa, oats, wheat, or whatever you want in your mix, and they will usually add the minerals & vitamins, then bag it up in either 50 to 100 lb sacks for you. If you contact Purina they are usually helpful in finding a custom mill that is near you, even if they are a competitor. Most custom mills belong to the Amish again.
Fourth, I look for sales especially at roadside fruit & veggie stands, and I buy my flocks whatever is in season, but isn't fit for human consumption, such as cracked watermelons, pumpkins, apples etc...They will bring you bushels of bruised fruits & veggies just to get rid of it. Also if you tell them that you will be feeding it to your flocks, tend to cut you a deal if you buy in bulk, 4 or 5 melons instead of just one. Get Old Jack o'latern pumpkins after Halloween, (Pumpkins & seeds are great for Deworming your flocks as well).
Fifth, Find restaurants with Salad Bars. They throw away a ton of fresh veggies every night and day old bread too, just ask them about retrieving it. Do not feed your poultry flocks any meat.
Sixth, you can make your own Chicken Treats of Black fly larvae, if you can stand the smell of rotting flesh, (Of which I can, by my neighbors don't).
Hope this helps!