Can improved function of crop and gizzard reduce crop fill at broiler slaughter?

Chickens, like most other birds, have a crop on their esophagus in which they can store feed for a while. Before slaughter, it is important that the crop is emptied to avoid residual feed contamination during slaughter. To reduce the occurrence of so-called filled crops, routines are applied on farms before slaughter. This means, among other things, that the feed is removed some time before loading to stimulate the chickens to use the feed they have in their crop. If a carcass has feed residues in the crop at slaughter, the entire carcass must be discarded, unless the crop is manually cut away. In recent years, discards at chicken slaughter due to contents in the crop have increased despite the same routines as before being applied on farms.

The project contains four parts. In the introduction to the project, we investigate what the contents of filled crops consist of, and to what extent the contents of the crop at slaughter are a so-called reflux from the stomachs. We will also find out to what extent feed in the crop is utilized by chickens during transport and lairage at the slaughterhouse.

In the second and third parts of the project, we investigate the effects of feed coarseness and longer continuous periods of darkness on both the crop and gizzard development. This is done at SLU's experimental facility Lövsta outside Uppsala. 

The final part of the project is carried out on commercial chicken farms, where we evaluate the adaptations of feed, light or other factors that seem promising based on what has emerged during the course of the project.

Project group:

• Helena Wall, SLU
• Anna Silvera, Svensk Fågel
• Emma Ivarsson, SLU
• Josefine Jerlström, SLU
• Liv Jonare, SVA