Information

Welfare of meat chickens and meat breeding chickens: guidance

Detailed information about the needs of meat chickens and meat breeding chickens and how to meet these needs in accordance with good practice.


Annex 4: Cumulative Daily Mortality Rate (CDMR): worked example

The total mortality in the example below – a shed with 20,200 birds placed, one thinning and 549 birds dead in total – is 549/20,200 x 100 = 2.72%.  The CDMR is 2.85%.  In this example there is not much difference between the two figures, but this could have been greater if, for example, there had been high mortality in the house.

An Excel spreadsheet that keepers can use to calculate CDMR can be found at: https://www.gov.scot/publications/welfare-meat-chickens-mortality-rate-calculator/

(Please note that Excel does not round the numbers before calculating, which accounts for some apparent anomalies in the table below.)

Age of birds/Day

Number of birds in the house at the start of each day

Number of birds culled AND number of birds found dead each day

Daily mortality rate

Cumulative Daily Mortality Rate (CDMR)

1

20200

29

0.1436

0.1436

2

20171

20

0.0992

0.2427

3

20151

15

0.0744

0.3172

4

20136

15

0.0745

0.3916

5

20121

19

0.0944

0.4861

6

20102

10

0.0497

0.5358

7

20092

15

0.0747

0.6105

8

20077

20

0.0996

0.7101

9

20057

10

0.0499

0.7600

10

20047

12

0.0599

0.8198

11

20035

10

0.0499

0.8697

12

20025

8

0.0400

0.9097

13

20017

10

0.0500

0.9596

14

20007

9

0.0450

1.0046

15

19998

20

0.1000

1.1046

16

19978

15

0.0751

1.1797

17

19963

9

0.0451

1.2248

18

19954

8

0.0401

1.2649

19

19946

10

0.0501

1.3150

20

19936

19

0.0953

1.4103

21

19917

10

0.0502

1.4605

22

19907

8

0.0402

1.5007

23

19899

10

0.0503

1.5510

24

19889

9

0.0453

1.5962

25

19880

21

0.1056

1.7019

26

19859

14

0.0705

1.7724

27

19845

27

0.1361

1.9084

28

19818

12

0.0606

1.9690

29

19806

6

0.0303

1.9993

30

19800

22

0.1111

2.1104

31

19778

31

0.1567

2.2671

32

16548

19

0.1148

2.3819

Thinned

33

16529

21

0.1270

2.5090

34

16508

12

0.0727

2.5817

35

16496

10

0.0606

2.6423

36

16486

8

0.0485

2.6908

37

16478

26

0.1578

2.8486

Cleared

Contact

Email: Kirsten.Foubister@gov.scot

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