Executive Summary

112
Hens observed
11
Non-productive hens
101
Productive hens
952
Total eggs collected
9.4
Mean eggs per hen
41.6%
Cream eggs (most frequent)
35%
Brown eggs
23.4%
White eggs
33 of 101 productive hens (32.7%) produced eggs in more than one colour category during the 2-week period — confirming this observation. Three hens produced eggs of all three colours (White + Cream + Brown).

1 Study Context

1.1 Background & Emails

During the two-week observation period (10–24 February), individual egg production and shell colour distribution varied among hens. Cream coloured eggs were the most frequent (41.6%), followed by brown (35.0%) and white eggs (23.4%). The mean egg production per hen over the study period was 8.5 eggs, indicating moderate short-term laying performance.

— Mekonnen Tilahun (data collector)

Please note that the category brown (polygenic trait) is not as brown as the commercial brown egg-layer, nor is white the snowy white from the commercial white egg layer (which, if I remember correctly, is the non-synthesis at all of protoporphyrin — a mutation on the Z chromosome).

— Olivier

I noticed a number of birds had eggs in multiple categories — white/cream and/or cream/brown… Is this correct?

— Anu
Note on colour categories: As noted, the ‘brown’ and ‘white’ categories here are intermediate phenotypes, not the deep brown or snowy white of commercial layer breeds. The Tilili flock colours span a continuum from white through cream to light brown. Why some individual hens produce eggs across more than one category is not yet fully understood: it may reflect underlying genetic variation, observer-dependent classification at the white/cream or cream/brown boundaries, or natural day-to-day variation in pigment deposition. Further investigation would be needed to determine the cause.

1.2 Data Sources

File Contents Rows Period
Eggcolor.csv One row per hen: White, Cream, Brown egg counts; Total Egg Count (TEC); Average Egg Weight (AEW) 112 10–24 Feb 2025
raweggcolordata.csv One row per hen: Daily egg weight (g) for each of the 15 days (Feb 10–24); total count; average weight 112 10–24 Feb 2025

2 Egg Production Statistics

2.1 Overall Production Summary

Metric Value
Total hens in dataset 112.0
Non-productive hens (0 eggs) — incl. ID 9377 duplicate 11.0
Productive hens (TEC ≥ 1) 101.0
Total eggs collected (all hens) 952.0
Mean eggs per productive hen 9.4
Median eggs per productive hen 11.0
Minimum eggs (lowest producing hen) 1.0
Maximum eggs (highest producing hen) 14.0
Observation period (days) 15.0
Data issue — Duplicate hen IDs detected. The table below lists all IDs that appear more than once. Both records are retained in the analysis but must be resolved in the field.

2.2 Duplicate ID Detail

Both records for duplicate ID(s): 9377 — from Eggcolor.csv
Source # Hen ID White eggs Cream eggs Brown eggs Total eggs (TEC) Avg weight (AEW, g)
Eggcolor.csv 1 9377 NA 3 NA 3 50.4
Eggcolor.csv 2 9377 3 NA NA 3 49.0
Both records for duplicate ID(s): 9377 — from raweggcolordata.csv (daily weights)
Source # Hen ID Total eggs (raw) Avg weight (g)
raweggcolordata.csv 1 9377 3 50.40000
raweggcolordata.csv 2 9377 3 48.96667
What the duplicate means:
  • Record 1 (ID 9377): 3 Cream eggs, average weight 50.4 g
  • Record 2 (ID 9377): 3 White eggs, average weight 49.0 g
  • These two records have different colour classifications and different weights — they cannot be the same hen on the same days.
  • Most likely: two different hens were given the same ear-tag number . The field team should check the physical tag or ringing records.

2.3 Distribution of Eggs per Hen

3 Egg Shell Colour Distribution

3.1 Overall Colour Proportions

Colour Total Eggs % of All Eggs Hens Producing
Cream 396 41.6% 59
Brown 333 35% 47
White 223 23.4% 31
Total 952 100% 101

3.2 Egg Colour Profile — Each Productive Hen

4 Anu’s Insight: Multi-Colour Hens

4.1 Confirmation

Confirmed: yes, some hens produced eggs in more than one colour category. A total of 33 hens ( 32.7 % of productive hens) recorded eggs in more than one colour category during the 2-week observation period. The cause is not certain. One possible explanation is that egg colour in this flock spans a continuum (white → cream → brown), and the boundaries between categories may not always be sharp — meaning a hen's eggs could straddle a boundary depending on the observer or the day. Underlying genetic variation is another possibility, but this would need to be verified with more structured data.

4.2 How Many Hens per Colour Category Count?

Colour categories laid Number of hens % of productive hens
1 colour only 68 67.3%
2 colours 30 29.7%
3 colours (all) 3 3%

4.3 Colour Combination Frequencies

How many hens produced each colour combination
Colour Combination Number of Hens % of Productive Hens
Cream 27 26.7%
Brown 23 22.8%
Cream + Brown 20 19.8%
White 18 17.8%
White + Cream 9 8.9%
White + Cream + Brown 3 3%
White + Brown 1 1%

4.4 Visual: Colour Combination Breakdown

4.5 Individual Multi-Colour Hens

33 hens that produced eggs in more than one colour category
Hen ID White eggs Cream eggs Brown eggs Total eggs Avg weight (g) Colour combination
9114 1 8 1 10 53.3 White + Cream + Brown
9187 1 7 1 9 49.0 White + Cream + Brown
8722 1 5 1 7 55.1 White + Cream + Brown
8655 5 8 NA 13 59.8 White + Cream
8940 7 6 NA 13 49.4 White + Cream
8476 NA 7 5 12 53.7 Cream + Brown
8935 6 6 NA 12 52.3 White + Cream
9190 NA 6 6 12 49.0 Cream + Brown
9195 NA 6 6 12 53.8 Cream + Brown
8490 5 6 NA 11 53.5 White + Cream
8670 NA 9 2 11 55.6 Cream + Brown
8863 7 4 NA 11 50.6 White + Cream
8925 NA 7 4 11 50.7 Cream + Brown
9017 NA 4 7 11 55.6 Cream + Brown
9097 NA 6 5 11 50.2 Cream + Brown
9205 NA 6 5 11 48.5 Cream + Brown
9294 NA 5 6 11 50.5 Cream + Brown
9305 NA 7 4 11 51.8 Cream + Brown
9322 6 5 NA 11 47.8 White + Cream
8775 NA 5 5 10 54.2 Cream + Brown
8833 5 5 NA 10 56.7 White + Cream
8919 NA 2 8 10 55.8 Cream + Brown
9276 NA 6 4 10 50.0 Cream + Brown
9409 NA 6 4 10 52.7 Cream + Brown
8581 5 4 NA 9 52.3 White + Cream
9362 NA 6 3 9 50.8 Cream + Brown
9427 NA 3 6 9 47.9 Cream + Brown
8466 NA 1 7 8 48.2 Cream + Brown
9004 NA 3 5 8 49.0 Cream + Brown
9019 NA 4 4 8 51.5 Cream + Brown
9011 NA 6 1 7 49.2 Cream + Brown
8517 4 2 NA 6 53.6 White + Cream
9135 1 NA 4 5 51.8 White + Brown
3 hens produced all three colour categories: IDs 8722, 9114, 9187 . These are the most striking cases of within-hen colour variation in this dataset. Whether this reflects true biological variation or inconsistency in classification at the colour boundaries is unclear. Photographing eggs at collection would help evaluate whether the white/cream/brown boundaries are being applied consistently.

4.6 Complete Per-Hen Colour Breakdown (All Productive Hens)

The table below lists every productive hen with the number and percentage of eggs in each colour category, making it easy to see at a glance which hens produced a single colour and which crossed categories.

Complete egg colour breakdown for all 101 productive hens. Red = 3 colours, Yellow = 2 colours, White = single colour.
Hen ID White (#) White (%) Cream (#) Cream (%) Brown (#) Brown (%) Total eggs Avg wt (g) # Colours Combination
9114 1 10 8 80 1 10 10 53.3 3 White + Cream + Brown
9187 1 11 7 78 1 11 9 49.0 3 White + Cream + Brown
8722 1 14 5 71 1 14 7 55.1 3 White + Cream + Brown
8476 0 0 7 58 5 42 12 53.7 2 Cream + Brown
9190 0 0 6 50 6 50 12 49.0 2 Cream + Brown
9195 0 0 6 50 6 50 12 53.8 2 Cream + Brown
8670 0 0 9 82 2 18 11 55.6 2 Cream + Brown
8925 0 0 7 64 4 36 11 50.7 2 Cream + Brown
9017 0 0 4 36 7 64 11 55.6 2 Cream + Brown
9097 0 0 6 55 5 45 11 50.2 2 Cream + Brown
9205 0 0 6 55 5 45 11 48.5 2 Cream + Brown
9294 0 0 5 45 6 55 11 50.5 2 Cream + Brown
9305 0 0 7 64 4 36 11 51.8 2 Cream + Brown
8775 0 0 5 50 5 50 10 54.2 2 Cream + Brown
8919 0 0 2 20 8 80 10 55.8 2 Cream + Brown
9276 0 0 6 60 4 40 10 50.0 2 Cream + Brown
9409 0 0 6 60 4 40 10 52.7 2 Cream + Brown
9362 0 0 6 67 3 33 9 50.8 2 Cream + Brown
9427 0 0 3 33 6 67 9 47.9 2 Cream + Brown
8466 0 0 1 12 7 88 8 48.2 2 Cream + Brown
9004 0 0 3 38 5 62 8 49.0 2 Cream + Brown
9019 0 0 4 50 4 50 8 51.5 2 Cream + Brown
9011 0 0 6 86 1 14 7 49.2 2 Cream + Brown
9135 1 20 0 0 4 80 5 51.8 2 White + Brown
8655 5 38 8 62 0 0 13 59.8 2 White + Cream
8940 7 54 6 46 0 0 13 49.4 2 White + Cream
8935 6 50 6 50 0 0 12 52.3 2 White + Cream
8490 5 45 6 55 0 0 11 53.5 2 White + Cream
8863 7 64 4 36 0 0 11 50.6 2 White + Cream
9322 6 55 5 45 0 0 11 47.8 2 White + Cream
8833 5 50 5 50 0 0 10 56.7 2 White + Cream
8581 5 56 4 44 0 0 9 52.3 2 White + Cream
8517 4 67 2 33 0 0 6 53.6 2 White + Cream
9312 0 0 0 0 14 100 14 47.1 1 Brown
9095 0 0 0 0 13 100 13 52.9 1 Brown
9147 0 0 0 0 13 100 13 53.9 1 Brown
9184 0 0 0 0 13 100 13 56.8 1 Brown
8738 0 0 0 0 12 100 12 57.4 1 Brown
8906 0 0 0 0 12 100 12 55.6 1 Brown
9199 0 0 0 0 12 100 12 48.9 1 Brown
9208 0 0 0 0 12 100 12 47.1 1 Brown
9226 0 0 0 0 12 100 12 55.6 1 Brown
9420 0 0 0 0 12 100 12 51.3 1 Brown
8840 0 0 0 0 11 100 11 53.5 1 Brown
9138 0 0 0 0 11 100 11 53.6 1 Brown
9236 0 0 0 0 11 100 11 57.2 1 Brown
9354 0 0 0 0 11 100 11 47.3 1 Brown
8636 0 0 0 0 10 100 10 47.7 1 Brown
8871 0 0 0 0 10 100 10 50.6 1 Brown
9146 0 0 0 0 10 100 10 47.2 1 Brown
8719 0 0 0 0 8 100 8 58.5 1 Brown
8910 0 0 0 0 8 100 8 55.3 1 Brown
9344 0 0 0 0 6 100 6 53.9 1 Brown
8784 0 0 0 0 4 100 4 45.9 1 Brown
9196 0 0 0 0 3 100 3 47.1 1 Brown
9119 0 0 0 0 1 100 1 55.2 1 Brown
9087 0 0 13 100 0 0 13 50.8 1 Cream
9116 0 0 13 100 0 0 13 50.7 1 Cream
8999 0 0 12 100 0 0 12 51.9 1 Cream
9005 0 0 12 100 0 0 12 51.6 1 Cream
9117 0 0 12 100 0 0 12 52.9 1 Cream
9398 0 0 12 100 0 0 12 56.0 1 Cream
8741 0 0 11 100 0 0 11 65.0 1 Cream
9003 0 0 11 100 0 0 11 49.8 1 Cream
9021 0 0 11 100 0 0 11 58.4 1 Cream
9140 0 0 11 100 0 0 11 53.2 1 Cream
9161 0 0 11 100 0 0 11 58.4 1 Cream
9310 0 0 11 100 0 0 11 57.0 1 Cream
9013 0 0 10 100 0 0 10 54.3 1 Cream
9295 0 0 10 100 0 0 10 51.8 1 Cream
8404 0 0 9 100 0 0 9 53.1 1 Cream
8580 0 0 9 100 0 0 9 56.3 1 Cream
9104 0 0 9 100 0 0 9 57.5 1 Cream
8781 0 0 8 100 0 0 8 50.9 1 Cream
8934 0 0 8 100 0 0 8 52.3 1 Cream
8913 0 0 6 100 0 0 6 59.5 1 Cream
9189 0 0 4 100 0 0 4 49.9 1 Cream
9326 0 0 4 100 0 0 4 47.4 1 Cream
9377 0 0 3 100 0 0 3 50.4 1 Cream
9085 0 0 2 100 0 0 2 51.5 1 Cream
8499 0 0 1 100 0 0 1 53.5 1 Cream
8657 0 0 1 100 0 0 1 56.1 1 Cream
9309 0 0 1 100 0 0 1 57.0 1 Cream
8831 14 100 0 0 0 0 14 46.4 1 White
8938 14 100 0 0 0 0 14 46.7 1 White
9185 13 100 0 0 0 0 13 44.9 1 White
8400 12 100 0 0 0 0 12 58.6 1 White
8772 12 100 0 0 0 0 12 57.5 1 White
8954 12 100 0 0 0 0 12 50.4 1 White
8997 12 100 0 0 0 0 12 49.1 1 White
9088 12 100 0 0 0 0 12 54.1 1 White
8413 11 100 0 0 0 0 11 53.6 1 White
8659 11 100 0 0 0 0 11 52.3 1 White
8605 9 100 0 0 0 0 9 48.8 1 White
8890 9 100 0 0 0 0 9 54.4 1 White
8844 8 100 0 0 0 0 8 58.0 1 White
9092 8 100 0 0 0 0 8 53.0 1 White
9016 4 100 0 0 0 0 4 49.1 1 White
9072 4 100 0 0 0 0 4 47.8 1 White
9377 3 100 0 0 0 0 3 49.0 1 White
8832 1 100 0 0 0 0 1 50.0 1 White

5 Daily Laying Pattern

Date Day Eggs collected
10 Feb 2025 Monday 55
11 Feb 2025 Tuesday 47
12 Feb 2025 Wednesday 74
13 Feb 2025 Thursday 71
14 Feb 2025 Friday 74
15 Feb 2025 Saturday 64
16 Feb 2025 Sunday 81
17 Feb 2025 Monday 68
18 Feb 2025 Tuesday 65
19 Feb 2025 Wednesday 60
20 Feb 2025 Thursday 69
21 Feb 2025 Friday 62
22 Feb 2025 Saturday 55
23 Feb 2025 Sunday 62
24 Feb 2025 Monday 45
Daily production range: 81 eggs were collected on Feb 16 (highest day), compared to 45 eggs on Feb 24 (lowest day). The daily mean was 63 eggs. Day-to-day variation may reflect natural laying rhythms, egg collection timing, or absence of some hens on certain days.

6 Egg Weight Analysis

6.1 Average Egg Weight by Dominant Colour

Dominant colour N Mean AEW (g) Median (g) Min (g) Max (g)
White 23 51.2 50.4 44.9 58.6
Cream 44 53.4 52.8 47.4 65.0
Brown 34 52.0 52.3 45.9 58.5

7 Summary

7.1 Key Findings

Finding Result
Observation period 10–24 February 2025 (15 days)
Total hens observed 112
Non-productive hens (TEC = 0) 11 (9.8% of total)
Productive hens 101 (90.2% of total)
Total eggs collected 952
Mean laying performance per hen 9.4 eggs (range: 1–14)
Most frequent egg colour Cream — 396 eggs (41.6%)
Least frequent egg colour White — 223 eggs (23.4%)
Hens with multi-colour eggs 33 hens (32.7%)
Hens producing all 3 colours 3 hens (IDs: 8722, 9114, 9187)
Duplicate hen ID detected ID 9377 (appears twice — verify in field records)
Data entry error detected Cell “b” in raweggcolordata.csv row 9017, day 22 (coerced to NA)

7.2 Recommendations

1. Multi-colour observation confirmed: Yes, 32.7 % of productive hens recorded eggs in more than one colour category. Whether this is driven by genuine within-hen biological variation or by inconsistent classification at the colour boundaries (or both) is not yet clear. Recommendation: photograph eggs at collection to check whether the white/cream/brown boundaries are being applied consistently.
2. Standardise colour classification: The ‘brown’ and ‘white’ categories in this flock are intermediate phenotypes, not the strongly pigmented colours of commercial breeds. Consider using a colour chart (e.g., Munsell scale) or reference photographs to ensure consistent classification across observers and collection days.
3. Fix data quality issues before next analysis:
  • Resolve duplicate ID 9377 — check ear tag in field records
  • Replace cell “b” in raweggcolordata.csv (row 9017, day 22) with the correct weight
  • Enforce unique hen IDs across all data collection sheets
4. Suggested next steps:
  • Photograph eggs at collection to document colour variation and calibrate classification
  • Track whether individual hens consistently produce the same colour or shift over time
  • Link colour data to pedigree to explore whether shell colour has a heritable component in this flock

Session Information

cat("Report generated:", format(Sys.time(), "%Y-%m-%d %H:%M:%S"), "\n")
Report generated: 2026-03-01 21:03:25 
cat("R version:", R.version$version.string, "\n")
R version: R version 4.5.1 (2025-06-13 ucrt) 
cat("Packages — dplyr:", as.character(packageVersion("dplyr")),
    "| knitr:", as.character(packageVersion("knitr")),
    "| kableExtra:", as.character(packageVersion("kableExtra")), "\n")
Packages — dplyr: 1.1.4 | knitr: 1.50 | kableExtra: 1.4.0 
cat("Data sources: Eggcolor.csv, raweggcolordata.csv\n")
Data sources: Eggcolor.csv, raweggcolordata.csv
cat("Observation period: 10-24 February 2025 (15 days)\n")
Observation period: 10-24 February 2025 (15 days)