"Youtube".
I'm so sorry.
STRONGLY recommend against Youtube diets, for yourself, or your chicks. There is plenty of room for reasonable debate - and it happens here on BYC almost every day, respectfully - about how much protein to offer what breeds, in what situations. How much fat is too much. When you can get away with feeding an enhanced calcium mix to Roos and non laying hens and pullets. Whether BSFL or Mealworms are a better treat, and how much to offer. The benefits of ACV...
But what is NOT in debate is the benefit of feeding a commercially balanced diet to your birds - because the possibility of creating a balanced diet meeting birds needs for various amino acids (to make up a complete protein) without resulting in massive amounts of fat or exhorbitant price tag (or both) by almost any backyard chicken owner is somewhere between nil and none. If you use the search engine, you will find numerous threads (roughly weekly) by new owners feeding very expensive whole grain organic feeds to their birds, who are suffering vitamin deficiencies as they pick out their favorites (according to flock order) and ignore the powdery vitamin/mineral supplement the feed company added to make that corn, barley, soy, wheat mix into something that will support a modern chicken in something like top condition.
This is wisdom ^^^. Accept that, for now, you don't have the knowledge or experience to sort the good from the fad on Youtube regarding feeding your birds.
So, I'll try and touch on the rest of your questions.
My birds free range (flock below, in the signature) across an area of about 4.5 acres, but generally confine themselves to a 1.75 acre area of biodiverse polyculture (Basically, I've deliberately seeded it with everything I could get cheaply which might self-propagate in my climate, then let things go). I benefit from the fact that I'm in north Florida, mild climate with a long growing season. You've not indicated your location, or the nature of your pasture, but the more diversity it has, the less likely that birds will either gorge on particular treat, or find a dearth of some needed vitamin to maintain their diet. I do have to be careful when the muscadines are in season that they don't get too many.
Tractoring is similar to free ranging - there's a lot of overlap in practice and experience - but the fact is, for good or ill, your birds are stuck eating whatever is in the tractor. Makes it easier to keep them away from the bracken fern, for instance, but harder to ensure that what they are offered is nutrient diverse. Just moving them from place to place on the fescue isn't going to cut it.
I feed my birds once in the evening, so they all come "home" to roost in one of the runs feeding them a complete commercial blend in quantity (adjusted seasonally) to ensure they go to bed with full crops, then are eager to free range when I open the gates in the morning. That works for me. My flock appears healthy, they show good weight gain, decent egg production, there's always a batch or three growing out - and I'm looking at the insides of a couple once a week as I cull.
My management practices in this regard are almost unique among the regular posters here at BYC. Thus, my experience in this regard should be considered an anecdote, not data. You are welcome to duplicate, but I make no guarantees.
My experience is that free ranging reduces my feed bill somewhat - around 25 - 30%, not insignificant when you have 50+ birds, but its not a free ride either. I have also fermented feed in the past. I now serve wet mash. Both are ways of ensuring that very important, vitamin and nutrient enriched fine powder in the whole grain feeds actually get eaten. Also substantially reduces waste for those of us feeding crumble (which, honestly, oft looks like powder at the bottom of a 50# bag). I have nothing against fermenting - it happens rapidly in my environment - it just didn't deliver the promised savings in food consumption (but as my birds already free range, it would have been unreasonable to expect big savings). Best guestimate is a savings between 10% and 15% on feed when I fermented. Right now, I don't have the space, but hope to return to it in the winter.
Whether you feed dry powder (crumble), dry pellets, wet mash, whole seeds, or sprouted, fermented whatever, its all going to the same place - the important thing is that the birds get the nutrition they need, not that they have a textural experience while eating. You can still feed them scratch, fruits or veggies from the kitchen*, from sprouting trays, mealworms or whatever as treats - but those treats should not exceed 10% of their daily diet by weight in order to maintain the balanced, nutritionally complete diet that they need.
*with a few to avoid, of course
I think that covers it. I can provide no shortage of studies over the past 40-50 years regarding the nutritional needs of modern birds, particularly modern layers or modern meaties which generally reach the same conclusions. That's science. I can offer my own experience - that's anecdote, and should not be highly valued. and of course I invite you to compare with the experiences of others here, many who have owned and maintained chickens far longer than myself, who have experiences of their own to offer you. Then make the best decision you can, for your needs, with the information available and go forth on your chicken journey, adjusting (or not) based on what works for you and your flock.
