Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Institut Agro Rennes-Angers

Home page

Select laying hens adapted to cage-free systems

Thesis : Select laying hens adapted to cage-free systems
The recent development of electronic nests enables to consider the selection of laying hens in conditions close to commercial cage-free systems.

Why select laying hens in cage-free conditions?

In European Union, 50% of commercial laying hens were reared in cage-free (soil, free-range, and organic) systems in 2018, 30% back in 2009, and 8% back in 1996 (ITAVI, 2019). These systems provide for laying hens living conditions that consider their sensitivities better. Today, laying hens are mainly selected in individual cages, to enable individual recording performance. The rearing conditions of the nucleus are now very different from those of commercial hens, especially in cage-free systems. Indeed, in these systems, hens are raised in a large group and must lay in nests to ensure eggs collection. The majority of eggs laid off-nest cannot be marketed because they are broken by hens or soiled with droppings. Collecting these eggs is also laborious work for the farmer as it must be collected by hand. Selecting hens on nesting behavior is an opportunity to reduce this off-nest laying.

How to record the hen’s nesting behavior?


Figure 1: Principle of electronic nest

Some electronic nests were developed by the breeding company Novogen to record nesting behavior under cage-free conditions (figure 1). Little is known about the genetic background of nesting behavior traits, such as time of entry or time spent in the nest. However, these traits could be the origin of competition of hens for nests, potentially leading off-nest laying. Electronic nests also make it possible to measure egg quality traits (with egg-hen awarding) as well as reproductive rhythm traits, such as the number of clutches (figure 2), already known in individual cages to improve the number of eggs laid by selection. (Chen and Tixier-Boichard, 2003; Wolc et al., 2019).


Figure 2: Laying patterns in nests of three hens (A: short clutches, B: long clutches, and C: clutch without pause) recorded with electronic nests for 140, between 24 to 43 weeks of age. Blue points represent eggs laid, and blue lines connect eggs when there is no day without data that separate the eggs, i.e. a pause day (green triangles) or an egg laid off-nest (red arrows).

Aims of the thesis

This thesis aims to acquire knowledge to optimize the breeding program of laying hens reared in cage-free systems. Our objectives are:

  • Study the genetic background of nesting behavior traits and reproductive rhythm traits as well as their genetic correlation with the laying rate in the nest and egg quality traits.
  • Study the genotype-by-environment interactions (cage and cage-free) for traits measured in the two types of breeding systems.
  • Identify the relevant traits to be included in the breeding program of hens adapted to cage-free systems.

Lorry Bécot is working on this subject since February 2020 for 3 years. He is supervised by Pascale Le Roy and Nicolas Bédère in the genetic and genomics team.


Lorry Bécot : lorry.becot[at] (Ph.D. student);
Pascale Le Roy : pascale.le-roy[at] (supervisor);
Nicolas Bédère : nicolas.bedere[at] (co-supervisor).


  • Chen C., et Tixier-Boichard M., 2003. Correlated responses to long-term selection for clutch length in dwarf brown-egg layers carrying or not carrying the naked neck gene. Poult. Sci. 82:709–720. DOI.
  • ITAVI, 2019. Situation du marché des œufs et ovoproduits - Edition novembre 2019. 11p.
  • Wolc A., Jankowski T., Arango J., Settar P., Fulton J.E., O’Sullivan N.P., et Dekkers J.C.M., 2019. Investigating the genetic determination of clutch traits in laying hens. Poult. Sci. 98:39–45. DOI.