What the chicks of a ISA Brown and a Olive Egger look like and lay, worked out from both breeds' standards.
A ISA Brown hen crossed with a Olive Egger rooster gives you what keepers call a first-generation (F1) cross. About 50–100% of the pullets should lay olive eggs (some may be green); the others lay brown. Most chicks (50%) get a pea comb. Expect a medium bird, a top layer, calm, the average of the two parents.
Preset to a ISA Brown hen and a Olive Egger rooster. Change either side to see how the blue gene and the brown coat move the shell colour.
He never lays, so his blue gene is read from his mother's eggs.
Probably Olive (possibly Green): 50–100% blue-based; otherwise Brown.
Brown shade shifts with a hen's age, diet and stress, so identical genes still lay a little differently. Speckling and bloom are cosmetic and not modelled.
| Trait | ISA Brown hen | Olive Egger rooster | Chicks |
|---|---|---|---|
| Comb type | Single | Pea | Pea 50% · Single 50% |
| Barring | Not barred | Not barred | Not barred |
| Fibromelanosis | Absent | Absent | Absent |
| Skin color | Yellow | White | White 50% · Yellow 50%yellow depends on a hidden carrier, so it could be 0%; a hatch or a known genotype can confirm (uncertain) |
| Leg color | Yellow | Slate | varies: polygenic, parents differ |
| Trait | ISA Brown | Olive Egger | Chicks |
|---|---|---|---|
| Frame height | medium | medium | medium |
| Egg production | top layer | good layer | top layer |
| Broodiness | never broody | rarely broody | rarely broody |
| Docility | calm | calm | calm |
| Bone density | medium | medium | medium |
| Foraging skill | decent forager | good forager | good forager |
| Cold hardiness | fairly hardy | cold-hardy | cold-hardy |
Chicks land near the average of the two parents for these traits. Reaching one parent's extreme takes another generation of selection.
This is the breed-standard version. Add your flock, set a breeding goal, and the pairing engine ranks every hen and rooster you own against it. Free for up to 15 birds.
Checked September 2026. Hybrids and breeds no reference covers are marked approximate. Egg colour on these pages follows one rule: Brown is any shade a buyer would call brown; Cream/tinted is off-white.