The simplest approach for a mixed flock of roosters and hens is to use a general-purpose “all flock” or grower feed as the base diet, then offer oyster shell on the side so hens can get the extra calcium they need without putting roosters at risk. This works because roosters and laying hens have genuinely different nutritional needs, and the wrong feed can cause serious health problems for one or the other.
Why Roosters and Hens Need Different Diets
Laying hens require 3 to 4 percent calcium in their diet to produce strong eggshells without depleting their own bones. That’s a lot of calcium, and layer feeds are formulated specifically to deliver it. Roosters, on the other hand, have no use for that much calcium. In non-laying poultry, calcium concentrations above 2 percent can cause kidney damage, urate deposits on internal organs and joints (a condition called visceral gout), and even seizures. Feeding a rooster standard layer feed day after day is a real health risk.
Protein needs also differ. A laying hen does well on about 16 percent protein, while a rooster maintaining his body weight doesn’t need quite that much. Neither bird is harmed by moderate protein levels in the 15 to 16 percent range, which is why a grower-type feed works as a shared base.
The Best Base Feed for a Mixed Flock
If you keep roosters and hens together, skip the layer feed entirely as your main ration. Instead, use an “all flock” feed or a grower feed with around 15 to 16 percent protein and no added calcium beyond what all chickens need. This keeps roosters safe from calcium overload while still giving hens adequate protein and general nutrition.
The calcium gap for your laying hens gets filled separately. Put crushed oyster shell in a small dish or hopper where your birds can access it freely. Hens instinctively eat oyster shell when their bodies need more calcium for egg production, and roosters typically ignore it because their systems don’t demand it. If your hens leave the oyster shell untouched, they’re getting enough calcium from the feed itself. Keep it available at all times regardless.
Feeding Chicks Through Each Growth Stage
Baby chicks start on a starter feed containing 18 to 20 percent protein from hatch through about six weeks of age. This higher protein supports rapid early growth for both males and females.
At six weeks, switch to a grower feed with 15 to 16 percent protein. Some feed brands offer a “developer” feed you can substitute after about 14 weeks, which drops protein slightly to 14 or 15 percent and helps prepare pullets for egg production. At this stage you still don’t need to separate males and females, since neither sex needs extra calcium yet.
The split happens around 18 to 20 weeks, when pullets start laying their first eggs. If you’re keeping the flock together, this is when you’d switch from a standard grower to an all-flock feed and begin offering oyster shell on the side. If your hens live separately from roosters, you can put the hens on a dedicated layer feed (about 16 percent protein, 3 to 4 percent calcium) at this point.
Treats, Scraps, and the 90/10 Rule
Both roosters and hens enjoy kitchen scraps and foraging, but treats should make up no more than 10 percent of the total daily diet. The other 90 percent needs to come from a complete, balanced feed. Going beyond that ratio dilutes the vitamins, minerals, and protein your birds depend on, which shows up as thinner eggshells, poor feather quality, and lower energy over time.
Good treat options include leafy greens, berries, watermelon, cooked rice, mealworms, and most vegetables. Scratch grains (cracked corn, wheat, oats) count as treats too, not a replacement for feed. They’re high in energy but low in protein and vitamins, so use them sparingly, especially in warm weather when birds need less extra calories.
Foods That Are Dangerous for All Chickens
A few common foods are genuinely toxic to both roosters and hens:
- Avocado pits and skins contain persin, a compound that causes respiratory failure in poultry. The flesh carries lower levels but is still best avoided.
- Dry or raw beans contain toxins that are almost always fatal to chickens. As few as three or four raw beans can kill a bird within an hour. Soaking alone doesn’t neutralize the toxin, and slow cookers don’t reach a high enough temperature. Beans must be fully boiled before feeding.
- Chocolate contains theobromine and caffeine, both of which damage the heart and digestive system. Even a small amount can cause cardiac arrest, with dark chocolate being the most dangerous.
When in doubt about a food, don’t offer it. Chickens forage broadly, but their small body size means toxins concentrate quickly.
Grit: A Separate but Essential Supplement
Oyster shell is sometimes confused with grit, but they serve completely different purposes. Oyster shell is a calcium source that dissolves in the digestive system. Insoluble grit, usually small granite pieces, stays in the gizzard and acts like teeth, grinding up whole grains, seeds, and fibrous plant material so your birds can actually digest them.
Chickens that free-range on soil and gravel usually pick up enough natural grit on their own. Birds kept on soft bedding or in enclosed runs without access to the ground benefit from a dish of appropriately sized granite grit. Like oyster shell, offer it free-choice and let the birds self-regulate. Both roosters and hens need grit equally, so there’s no reason to separate it.
Practical Setup for a Mixed Flock
A feeding station for a flock with both roosters and hens looks like this: one or more feeders filled with all-flock or grower feed, a small dish of crushed oyster shell, a small dish of granite grit (if your birds don’t free-range on natural ground), and clean water at all times. That covers every nutritional need for both sexes without putting either at risk.
If you notice thin or soft eggshells, your hens may not be eating enough oyster shell. Try moving the dish closer to where they spend the most time, or switch to a slightly coarser oyster shell product that some hens prefer. If a rooster starts eating from the oyster shell dish regularly, which is uncommon but possible, you may need to relocate it to an area the hens can access but the rooster can’t, or offer it during the hours you can supervise.