chicken crops

I'm searching for information on readily available seeds or seed mixtures available on the market to grow, to feed chickens by foraging in Portugal.

Are you using any specific supplier or just apply some other recipe of your own?

I have done some research online, but it's useless if i can't get a supplier, so better look at the problem the other way around and see if there is any offer on the market.

I'll go down to the local store tomorrow to see what they might have, but doubt they will have anything useful, bet they are going to try and sell me some chicken feed. Any feedback is appreciated.

I'm just starting up on agriculture, don't really have a clue on how things are done, just a lot of internet browsing searching for answers...

Amaranths would grow beautifully in your climate, the chickens love the seeds. Sunflowers are another favorite.
If you have a chicken run I'd suggest growing a fruiting vine over top. Shade plus food!
I sprout lots of grains for my chickens, wheat and rye are their favourite. I've also used a seed mix called "forage mix" that I grew in succession for constant food supply.
Do you have a compost bin?

Here's what I grow specifically for my chickens:

Grass

Dandelions

Chickweed

Goosegrass/cleavers

Dock and plantain

Mallow

Alfalfa/lucerne

Various clovers, including white and crimson

Winter rye

Mint

Chard

Various brassicas (cabbage, kale, mustard, etc)

Sorrel

A lot of these are weeds, and I didn't plant them myself! My nine chickens live on a very small suburban lot, and I rotate them through four or five different sections, usually moving them once a week. They eat more than just the above, including some of my ornamentals (for instance, they seem to really like rose leaves), bugs, and I also provide chicken feed.

The chard and brassicas come from seed I save myself, and I keep it in a jar labeled "chicken mix" along with winter rye, crimson clover, and some other random seeds. The rye, crimson clover, and alfalfa I bought in bulk as green manure. Any sort of pasture seed mix, or cover crop mix would be fine to grow on as chicken forage, and mixed seed will be better than just one variety of seed.

Bear in mind you'll probably have to grow the forage for several months or even up to a year before you can let chickens onto it; they will destroy it if it's not well established--ask me how I know

A google search for "chicken forage seed mix" turned up several interesting pages.

https://www.google.com/search?q=forage+mix&oq=forage+mix&aqs=chrome..69i57j69i60&sourceid=chrome&es_sm=93&ie=UTF-8#safe=off&q=chicken+forage+seed+mix

There are few things chickens will not eat, and there are many things they will thrive on that many don't think of. They love any kind of meat or dead animals....either cooked up (I use my solar oven, so the energy is "free"), or simply allowed to ripen and become maggoty. Black soldier flies are easy to raise and they can eat the chickens' own manure (as well as every other kind of manure including your own!) and all manner of other vile stuff, and turn it into feed. I feed my layers on leached, boiled acorns.... If you are near a town, the dumpsters can likely feed them too......