There has been considerable discussion about the relative egg production between automatic and manual nest box systems. Table 1 shows some key differences between manual and automatic nest types, where similar egg numbers can be expected when both systems are managed to a high standard.
Over ten years ago it would have been preferred to use manual nests as a method of collecting eggs for breeding turkeys. At the time, the use of automatic nests was affecting the number of settable eggs laid by each female. It was considered that the difference in the number of eggs laid by each female between the different types of nests ranged between five and ten eggs in favour of manual nests. Today the difference has been reduced to a minimal amount if there is even a difference (Fig.1).
Field experience has shown that it can be easier to get the female to ‘accept’ a manual nest as it is more natural, however, the reduction or elimination of this gap is essentially due to two factors: The improvements of automatic nests that increasingly tend to fully satisfy the needs of females while reducing the risk that the collection mechanisms will damage or break the eggs. The genetic improvement of the breeds, has led to having more robust, stronger and dynamic birds that take full advantage of the possibilities offered to them by automatic nests. Not all aspects relating to egg collection find a positive solution in the use of automatic nests. One of the problems that remains, and indeed is emphasised, is floor eggs (eggs laid on the ground). This can even be found in flocks where females are perfectly trained to automatic nests and from internal data, it’s revealed there’s a higher percentage of floor eggs in automatic nests compared to manual nests.
It is obvious that the greater the number of eggs laid on the floor, the greater the risk they can break or become dirty, compared to eggs laid inside the nests. This problem can be improved by carrying out a manual collection of eggs that have been laid on the floor, straight after each automatic collection of the nests. This reduces the time that these eggs remain on the litter and consequently lowers the risk that they can get broken or get dirty (Fig. 2).
A second problematic feature with all types of automatic nests is that it can be difficult to organise and manage the broody control, including the operations that allow the identification and treatment of females. Eggs laid by females inside the nests must be collected several times a day; generally, the minimum number of daily collections is eight for manual nests and twelve for automatic nests.
At the time of each collection, it is essential to push all females out of the nests, regardless if they have laid an egg. Females can resist coming out of the nests and this attitude is emphasised more during and immediately after the peak of production (third – fourth week of lay). This is because the female begins to develop the tendency to become broody, where a female wants to sit on the egg and start the incubation process. The more time the female spends inside the nest, the more instinct for sitting/incubating the egg will develop, which increases the levels of prolactin, (the hatching hormone), this is why it’s important to push the females off the nests during all collections.
The instinct to sit on the egg is natural, especially in summer cycles and can cause significant economic damage, leading to the female not producing eggs anymore. For this reason, identifying females that are becoming broody early is key (Fig. 3).
Examples of commonly used automatic nest systems for turkey breeders are those manufactured by MGH and Vencomatic (Fig. 4).
The systems produced by Vencomatic and MGH work differently with regard to the trap mechanism, bird push-off from the nest and egg collection. MGH traps can be closed as required whilst Vencomatic traps are continuously open at all times. The MGH trap operates by the bird pushing the nest trap paddle on entering the nest which closes the trap behind the bird; the bird can exit easily when she wants to. The Vencomatic trap closure is triggered by the weight of the bird on the nest floor upon entering the nest. Bird push-off in the Vencomatic is accomplished by raising the nest floor which also rolls the egg onto the belt at the front of the nest. In the MGH nest the rear panel of the nest pushes the bird off and a flap at the bottom of the panel rolls the egg onto the belt when it returns.
The push-off process takes 90-120 seconds to prevent bird stress and damage to the egg. The egg belt for the Vencomatic nests is at the front of the nest under the front step-up and with the MGH nest the belt is accessible from the rear of the nest. It is important to consider the design and angle of ramps used with auto-nests. The ramp height relative to the nest should allow easy entry and exit for the females. Ramps ideally should be flat and short so that the females fall away from the nest after push-off, making sure that the females cannot occupy the nest for longer than necessary.
Automatic nest boxes have had undeniable improvements and the number of companies that have equipped themselves with this type of nest box in recent years has considerably increased, compared to those using manual nest boxes. Behind the decision to choose automatic over manual nest boxes are also some important additional reasons. The modern world is paying more attention to the well-being of the farm staff and it is undisputable that with automatic nests the workload of collecting eggs is considerably less stressful and tiring. Added to this is the difficulty, in many countries, of finding employees who agree to carry out these types of laborious jobs such as egg collection and therefore automatic nests become almost an obligatory choice.
