How to Get the Cosmo Brat
What this page helps you decide: which egg to hatch for the Cosmo Brat, and how many hatches to budget before it shows up
The Cosmo Brat is a Uncommon chicken, tier 2 of 10 on the rarity ladder that appears in the drop data. 3 eggs can hatch it, and the best published rate is 100% from the Grudge Egg — about 1 hatches before you should expect to see one. Below: every route in with the expected hatches worked out, where it sits among the 1 outcomes of that egg, how it compares with the other Uncommon chickens, and what we found when we checked the published percentages.
Which route is actually faster
The Grudge Egg drops it at 100%; the Nest Egg at 10%. In expected hatches that is roughly 10 times more work on the slower route. Supply is the catch. The Grudge Egg cannot be farmed on demand, so the better rate only helps once you are already holding one. If you are working with eggs you can produce yourself, the Scratch Egg is the route that actually applies, and you should budget the 9 hatches that implies rather than the headline number.
Where it sits inside the Grudge Egg
The Grudge Egg can hatch 1 different chickens. The Cosmo Brat is the 0th most likely of them, with 0 outcomes sitting below it on the table. At that position it turns up often enough that a dedicated farm is usually wasted effort — it arrives while you are chasing the rarer drops in the same egg.
Against the other Uncommon chickens
There are 20 Uncommon chickens in the current drop data. Ranked by best available rate, 0 of them are easier to obtain than the Cosmo Brat and 19 are harder. Nothing at this rarity comes easier, so if you want a Uncommon at all, this is where to start.
What the published table does not say
These rates come from a single community index rather than the game files, so we checked the arithmetic before using them. 9 of the 17 egg tables do not add up to 100 percent — across the set they run from 91 to 102 percent. The Grudge Egg table does add up, which is a small point in its favour. Rounded rates are good enough for deciding which egg to farm. They are not good enough for predicting any single hatch, and anywhere a rate is written as "under 1%" the true value could be several times smaller than the estimate above.
Step-by-Step
- Get hold of a Grudge Egg; it is not laid by any chicken you can keep, so this step is the real bottleneck.
- Hatch it repeatedly and budget around 1 hatches at the published 100%.
- Skip the Nest Egg route unless the faster egg is out of reach — it costs roughly 10 hatches instead.
- Treat it as a by-product: farm the Grudge Egg for its rarer outcomes and this one will arrive on the way.
Data Tables
| Egg | Published rate | Expected hatches | How you get that egg | Source table sums to |
|---|---|---|---|---|
| Grudge Egg | 100% | 1 | Currently unobtainable | 100% |
| Scratch Egg | 11% | 9 | Laid by the Cosmo Brat | 99% |
| Nest Egg | 10% | 10 | Laid by the Classic Rooster | 100% |
FAQ
How do you get the Cosmo Brat in Grow a Chicken Fighter?
Hatch the Grudge Egg. It drops the Cosmo Brat at 100%, which works out to roughly 1 hatches before you should expect one.
What rarity is the Cosmo Brat?
Uncommon, which is tier 2 of the 10 rarity steps that appear in the drop data.
Is the Cosmo Brat worth farming for?
Not on its own. It is the 0th most likely outcome of the Grudge Egg, so it arrives while you farm that egg for something rarer.
Is the Nest Egg worth using for it?
Only when the Grudge Egg is out of reach. The rate there is 10% against 100%, which is about 10 hatches instead of 1.
Does the Cosmo Brat lay anything?
Yes — the Scratch Egg at 100%. Keeping one on the plot is how you produce that egg.
Sources
- Community Grow a Chicken Fighter Eggs Index (community drop table) — Single community source for every drop rate on this page. Captured 2026-08-27. We recomputed each table: 9 of 17 do not sum to 100%, so the rates are treated as rounded throughout.