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Updated S-line CO2NTROL™ profiles

For many years now, Petersime’s Embryo-Response Incubation™ systems have been providing significant gains in hatchability, chick quality and post-hatch performance. One of the key factors is the CO2NTROL™ system, which is standard installed on all S-line setters and hatcher configurations. Recent field trials and research have led to refinements of Petersime’s incubation profiles regarding CO2. These are based on two objectives: reducing early incubation mortality and improving chick yield. Chick yield is the weight of the chick at hatch as a percentage of the egg setting weight.  

 By Roger Banwell, Hatchery Development Manager

1. Limited ventilation at the beginning of the incubation cycle

The graph bellow shows the updated CO2-curve. 

The updated CO2 curve

The main modification to the previous profile can be found during the first 6 days of incubation. Whereas in the past, there was almost no ventilation at all at the beginning of the incubation cycle, now a reduced level of ventilation is applied. This leads to a slightly slower, controlled build-up of CO2 inside the incubator cabin. The CO2-peak is now reached by day 6 rather than by day 4 in the previous program.

Extensive research has indicated that this small amount of ventilation during embryonic development has several important advantages.

  1. A first factor is an increase in the antimicrobial potential of the albumen (Fang et al., 2013). Changes occurring in the egg albumen during early incubation can influence the growth of Salmonella Enteritidis.
  2. A second factor is the albumen viscosity (the “thickness” of the egg white) and changes of the albumen pH value (acidity level) (Benton & Brake, 1996; Benton et al., 2001; Fang et al., 2012; Lapão et al., 1999; Peebles et al., 2000).
  3. By ventilating, any residual fumigation agent on the egg shells is removed, avoiding entry in the egg shell and damage to the developing embryo.
  4. A reduced amount of ventilation early in the incubation cycle allows for a small increase in weight loss. This makes it easier to reach the weight loss goal of 10-11% by transfer time to the hatcher (see article: Ventilation in the setter).
  5. Finally, the amount of condensation inside the incubator cabinet is lowered significantly.


2. Lower CO2 levels before transfer

The second main modification consists of lower CO2 set points in the period prior to transfer. This allows for increased ventilation and thus further weight loss. Moreover, an increase in the percentage of air cooling limits the use of water cooling. This reduces the water consumption in your hatchery.

This overall greater flexibility in weight loss leads to an optimum chick yield. Chick yield is the weight of the chick at hatch as a percentage of egg setting weight. A good chick yield (between 67 and 69%) indicates correct hatch timing and incubation parameters (Aviagen, 2013), and is important for post-hatch performance.

3. Variable peak CO2 set points

Thirdly, the updated CO2 profile has variable peak set points. These depend on the flock age of the eggs in the setter. The graph below shows the stepped program configuration with a suggested peak modification for flock age.

Variable peak CO2 set points

This variable set point of the CO2 peak allows for further refinements to the program based on flock age and/or post hatch performance feedback.

In practice

The standard configuration is available on the Petersime service website along with download and installation instructions. To download the file, first log on to the service website, then click here.

Petersime’s Hatchery Development Department strives to ensure the standard programs available to the clients are as optimal as possible. However, they are used in different climates, altitudes, flock types, storage times, breeder managements/nutrition, etc. Therefore, customer specific optimisation can only be achieved through good data analysis and feedback, in conjunction with good hatchery management.


  • Aviagen, How to measure chick yield
  • Benton CE, Brake J, The effect of broiler breeder flock age and length of egg storage on egg albumen during early incubation. Poultry Science, 1996, 75, 1069-1075.
  • Benton CE, Walsh TJ, Brake J, Effects of presence of a blastoderm on albumen height and pH of broiler hatching eggs. Poultry Science, 2001, 80, 955-957.
  • Fang J, Ma M, Jin Y, Qiu N, Huang Q, Sun S, Geng F, Guo L, Liquefaction of albumen during the early incubational stages of the avian embryo and its impact on the antimicrobial activity of albumen. Journal of Food, Agriculture & Environment, 2012, 10 (1), 423-427.
  • Fang J, Ma M, Jin Y, Qiu N, Ren G, Huang X, Wang C, Changes in the antimicrobial potential of egg albumen during the early stages of incubation and its impact on the growth and virulence response of Salmonella Enteritidis. Italian Journal of Animal Science, 2013, 11-17.
  • Lapão C, Gama LT, Chaveiro Soares M, Effects of broiler breeder age and length of egg storage on albumen characteristics and hatchability. Poultry Science, 1999, 78, 640-645.
  • Peebles ED, Gardner CW, Brake J, Benton CE, Bruzual JJ, Gerard PD, Albumen height and yolk and embryo compositions in broiler hatching eggs during incubation. Poultry Science, 2000, 79, 1373-1377.