More and more UK free-range and barn egg producers are looking to multi-tier/aviary systems as a means of maintaining bird numbers as legislation demands reduced stocking densities for new units and for all units from 1 January 2012.

This, in effect, is a reduction in stocking density of 23% from the 11.7 birds/sq m original stocking density.

However, one solution is to incorporate multi-tier systems in existing or new build houses, which effectively allows more birds to be housed within a given floor space area, as the tiers increase the usable space. Already a number of companies are offering multi-tier systems, among them being Newquip with the Big Dutchman Natura system.

Optimum performance

But a key question with the system has been how best to rear the birds to achieve optimum performance in lay? Based on continental experience, the advice is to rear birds in a multi-tier environment and not just providing the odd platform for the birds to jump on.

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The Tom Barron Group based near Preston decided to convert two 26,000 floor rearing houses to a multi-tier rearing system (Poultry World, February 2007, p34). Incorporating the system within the houses, which is approved by Freedom Food, allowed stocking density to be increased to 33,000 birds. A further two units have already come on stream and plans are ahead to convert more rearing sheds to the multi-tier system.

The flock was destined for a major egg producer in the midlands who had installed the same tier system. Tom Barron national pullet sales manager, Doug Kirkby, was naturally keen to follow the progress of the flock through lay.

Remarkable

On housing, birds were placed on the tiers and quickly began to move around them finding feed and water without difficulty. Many moved to the littered floor area but even at the end of their first day what was remarkable was that only a few birds had to be encouraged back to the tiered areas to roost.

“We have seen exactly the same behaviour where the majority of birds have returned to the slatted areas to roost in conventional free range units when reared in a multi-tier environment,” said Mr Kirkby.

“I am convinced of the benefits of encouraging chicks to learn to jump at an early age and move between tiers. But we are still learning and with subsequent flocks, we have moved feeders to ground level while keeping the drinkers above the slatted tiers which has encouraged even more bird movement,” said Mr Kirkby.

Performance in lay

But as he rightly says at the end of the day it is the performance of the birds in lay which really matters. And this first flock has not disappointed him. At the time of writing, the flock of ISA Warren birds was 70 weeks of age and had peaked at 95% and held production at more than 90% for some 30 weeks.

At 70 weeks, production was still in excess of 80% with anticipated egg numbers of 310 by 72 weeks.

Despite the high egg output, egg size was about 66g. Another feature was the low percentage of floor eggs for many weeks under 1%.

Feed intake has also impressed with the flock consuming in the region of 121g a bird a day. Mr Kirby calculates that this low feed intake coupled with the low percentage of floor eggs is reckoned to be worth about 75p a bird. A second flock is also performing above expectations having already achieved 94% peak production.

Mr Kirkby is finding more and more producers investigating the benefits of multi-tier systems particularly focusing on the advantages in building costs due to better stocking density coupled with the high level of performance and reduced feed conversion.

Benefits of multi-tiered laying systems

  • Increases usable space
  • Economic conversion in existing houses
  • Welfare friendly
  • Low floor eggs due to better egg recovery
  • High level of production
  • Calmer flocks
  • Improved environment as manure can be removed regularly
  • Reduced feed conversion
  • Improved liveability

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