How can I improve how I'm feeding my chickens?

[Sussex19]

Nothing wrong with beach shell - its how they would get it in nature. I offered the other suggestions as a convenient way to get a bit of extra P into birds needing extra calcium.

Chickens can't used plant-based phosphorus, your feed contains no animal sources which might provide trace amounts, and its Ca : P ratio is 5:2. Apart from egg shell creation, most biological processes exist in a ratio of 2:1, and most of the modern studies sugges tthat differences in digestion and nutrient absorbtion make a 5:3 ratio as fed a better choice for poultry, with 1% Calcium +/- being the baseline target, which then establishes the baseline for Phosphorus.

Of course, if you have a decent amount of P in your soils, and your birds are able to eat a significant amount of bugs, there's good chance (no guarantees of course) they are meeting the need that way.

Got it!
And that sound like a good idea, so I'll see what we can find.