Hi There and Welcome!
First, if you feed them anything but chick starter food, you'll need to provide them with grit so they can digest it. You can buy chick grit or get some course sand from Lowes or Home Depot. I've read that you should not get playground sand as it's too fine. I'm doing my chicks as sustainably as possible, which means re-using anything I can and buying as little as possible. So, I went out in the field and found holes in the ground where bees had been building little individual nests. When they do this, they make a little pile of dirt that is course sand. Why bees do this, I don't know but I figured it was about the right size. I used a spoon and just went around scooping these tiny piles of sand up until I had a pretty good amount. I put enough to fill the bottom of one of those flat wide tupperware like containers and put it int the brooder. The chicks loved it, ate a bit, played in it, slept in it. I also would go outside and get a shovelful of sod, dirt, grass and all and put it in their brooder, dirt side up. Loved that too, took dust baths in it and just had a good time messing around with it. I know they got some grit out of that too.
In terms of treats, they'll eat about anything but at first with each new thing, they tend to be a little hesitant. They need to warm up to anything new, as I'm sure you're noticing. I found a list of things they'll eat and that you shouldn't give them:
https://www.backyardchickens.com/a/chicken-treat-chart-the-best-treats-for-backyard-chickens
You want to limit the amount of treats you give them and I'd suggest sticking to high protein things, like chicken and hard boiled eggs. The reason is they need a very high protein diet (20%) so you don't want to give them so many treats that it causes their diet to become unbalanced. Also, chop it really small. I used a blender. Chickens have no teeth, of course so it helps if it's small, easier for them to grind up using the grit in their gizzards. Not mush but very small pieces.
For my chicks, I made them a treat daily, in the afternoon. It was a mix of chicken, hard boiled egg, lettuce and whole wheat oats, all cut up int he blender. The oats help them have good poos and I can tell you it works well.
The other advantage of treats (again, not too much) is that it helps them get used to you and associate you with good things. You can hand feed them sometimes, which helps you get close to them and them get used to you.
Oh, and I gave mine a lot of bugs. Not worms or slugs (they carry gape worms). Wasps that I'd killed before giving it to them, flies, centipedes, ticks, lady bugs. Dead or alive or stunned. I live in the country and we have no shortage of bugs! I was trying to imitate a mother chicken, who helps her chicks find bugs to eat. And, I wanted them to start learning to forage at an early age, thinking it might help them be better at it as they grow older. And, it sure is fun watching them play "I'll run and you try to get this bug." This BTW, is actually the way they break apart big bits of food so this game has a purpose. As they grab it from each other, they each get a bite and the bug or whatever it is is divided into smaller pieces.
Now, my 16 chickens are between 9 and 11 weeks old. They are nice sized, healthy and eat about every type of table scrap. Already, they forage very well for a good part of their own food. Today, they had some left over potato salad that I tried a new recipe with and we didn't like it. Chickens loved it! I still put it in the blender to make it easier for them, and add whatever I have on hand, a bit of leftover lettuce stalks, those green leafy things on the celery, whatever. I don't feed them a ton as they're now on chick grower food because they still need about 16% protein.
Here's a good article on this topic:
http://www.the-chicken-chick.com/2012/11/feeding-chickens-at-different-ages.html
Hope this helps. Great luck to you!
Guppy
