If your chickens are kept in a coop and run and you supply a commercially produced feed, preferably between 18% and 24% protein. And, if you only have females calcium at around 4% for regular layers, then the treats you mention are great fun for you but not quite so good for your hens.
The 10% only treats recommendation only makes sense for chickens kept in an average sized run.
If you fully free range or even if you let them out of the run for a couple of hours a day, then they will find all sorts of things to eat and it is not possible to maintain any regulation on their nutrient intake. Under these conditions (free range) I would scrap all the treats you mention, apart from the herbs in small quantities and consider feeding them a teaspoonful of meat or fish each once a day.
Chickens are omnivorous and most will happily eat meat and fish. The advantage to feeding meat and fish over the treats you mention is both meat and fish have all the necessary proteins and most of the vitamins and minerals your chicken needs.
You could split this in to two, or more treat sessions if you wanted, but bear in mind the teaspoonful limit per day.
You will still need to supply a commercial feed with the percentages mentioned above.
I like to give the free range chickens here treats, but the quantities are very small.
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To put this in perspective. I will give half a walnut split between 6 chickens for example, or a grape each per day.
They do get treats at roost time, after they foraged and eaten the commercial feed, but it's a level handful between 15 to 20 chickens.
Chickens love treats but the truth is too many of the wrong type of treats are just not good for the chickens long term health. They can cause their internal organs to accumulate fat which can lead to organ failure, give mobility problems and decrease their egg production and in more extreme cases cause long term reproductive issues.
Thanks for the info. I do feed crumble to Pixie. I give her the hard boiled egg every day or two (not consistent) and the other stuff I give her just because I read an article somewhere that what they don't want/eat they scratch into the ground and are kind like natural composters. To me, Egg production is not a priority.