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February 1, 2024 | by Sam Shafer
Floor egg laying continues to bedevil commercial egg producers and breeders using cage-free housing systems. Floor eggs -- also called "mislaid eggs" or "system eggs" -- are eggs laid outside the nest box, for example on the litter, slats, or tiered wire. As a result, contaminated eggs, broken eggs, and extra egg collection labor can lead to significant economic loss.
Now, a new comprehensive literature review -- the first such in 40 years -- brings us up-to-date on research and practice to prevent floor egg laying.
Efforts to reduce floor eggs go back more than a century, with the scientific research summarized in a major literature review in 1984, when cage housing systems predominated. With the rise of cage-free systems, the factors causing floor egg laying now may be more complex and the potential consequences of poor management even more costly.
This new review focuses on preventing floor eggs in cage-free systems by addressing the major causal factors and improving management during pullet rearing and onset of lay. It covers recent studies on nest box use, genetics, rearing and early training, the production cycle, and new technologies. There's also practice advice from online sources and interviews with commercial egg producers in Australia, where the reviewer is based.
The reviewer notes that much of the early research also applies to modern cage-free systems:
Highlights of more recent findings include...
Nest box use: If a hen uses the nest box during early lay and its features and microclimate do not change, then she's likely to use it for the full production cycle. Nest box design affects prelaying behavior, nest choice, and nest preference during lay. Variables include nest floor slope, lighting, nipple drinker location, curtain type and color, box construction material, size, height, and substrate type and depth, including "manipulable substrates" versus fixed flooring. For breeders, social dominance and gregarious nesting behavior particularly impact nest box use.
Genetics: Although modern birds are not so broody, they still exhibit characteristic prelay behavior 1-2 hours before lay -- searching for a nest site, sitting on the site, nest building -- and generally prefer to lay in discrete, enclosed spaces. Possible differences in floor laying between white and brown feather birds remains an open question. However, brown hens tend to be heavier, which influences how they use a tiered aviary, selecting lower perches and nest boxes. Differences in timing of oviposition and start of lay may impact rearing with knock-on floor laying effects.
Rearing and early training: General advice is to rear pullets in the same type of system used for the laying cycle, with access to perches no later than 4 weeks of age. Transition "like-to-like" benefits include better use of aviary upper levels during early-to-peak lay. Litter restriction helps deter floor laying, but it's also a risk factor for feather pecking.
Production cycle: Increased stocking density with greater nest space competition can increase floor eggs. Also, "enrichment devices," such as pecking stones and alfalfa bales, may increase floor eggs.
"Overall," the reviewer notes, "research across the laying period is limited as the key periods for behavioral manipulation are when the birds are younger."
New technologies: Floor robots designed to discourage litter nests and floor egg laying have lacked "robust evidence of their effectiveness," as hens "rapidly acclimate to the robot" and within weeks are riding it. However, robots for floor egg detection and collection have shown some success in reducing labor. Ongoing research using camera systems with "machine vision" has detected hens sitting on the floor, including corners.
"Ultimately," the reviewer states, "radio-frequency identification-enabled smart nest boxes that can track individual hens’ laying behavior may allow producers to detect poorly performing birds," including floor egg layers
What does this review mean for producers?
The full paper, titled "Floor egg laying: can management investment prevent it?" can be found in The Journal of Applied Poultry Research and online here.
Categories: Interpretive Summary