The present invention relates to a multi-level accommodation system for broilers consisting of at least one level comprising an endless conveyor belt, on which the broilers are present, which may be separated from each other by partitions disposed slightly transversely to said conveyor belt, means for supplying air and means for exhausting air. The present invention furthermore relates to a method for accommodating broilers by using such a multi-level accommodation system. The term ^" broiler ^" should be understood to include various kinds of poultry.

A multi-level accommodation system for broilers of this type is described in Dutch Patent Application No. 1002007, which was published on 6 February 1997. Tiltable bottoms, in which an air permeable cloth is present, are thereby used as accommodation. Aeration only takes place on both sides of such a multi-level system for broilers. One drawback of separate bottoms of this kind is the fact that the bottoms must be pulled forward and subsequently be tilted in order to load the animals and clean the system. For a conventional stable this is a highly labour- intensive activity. Another drawback of a multi-level accommodation system of this kind is the fact that the aeration being used is not sufficient for drying the manure, nor for supplying oxygen to the animals. In addition to that the emission of ammonia to the outside air is considerable, and in accordance with recent legisl ation on this field the emission of ammonia of newly marketed systems must be 50% lower than that of the current systems.

The object of the present invention is to overcome the above problems, whereby in particular the emission of ammonia to the outside air must be reduced to a minimum. In addition to that it is desirable to regulate the amount of air to be supplied to the broilers, thus creating optimal living conditions for the animals. It is known that if the amount of air being supplied is too low, the temperature will become

too high for the animals present on the level in question, whilst an excessive supply of air, the draught phenomenon, will lead to illnesses among the animals.

The multi-level accommodation system for broilers referred to in the introduction is characterized in that the conveyor belt comprises a part which is permeable to air and a part which is impermeable to air, whereby the conveyor belt is provided on at least one longitudinal side thereof with means for supplying air, which extend along substantially the entire length of the conveyor belt. It is preferred for the conveyor belt to be provided on both longitudinal sides with means for supplying air, which extend along substantially the entire length of the conveyor belt.

In this manner a multi-level accommodation system for broilers is obtained wherein the manure present on the conveyor belt is dried in an advantageous manner, as a result of which the emission of ammonia is reduced to a minimum. The air supplied on the bottom side of the conveyor belt passes through the air permeable part of the conveyor belt, thus drying the manure present on the conveyor belt, in particular that part of the manure which is in contact with the conveyor belt. In addition to that the air flow above the conveyor belt will also dry the manure on the side remote from the conveyor belt, so that a quick and complete drying of the manure is obtained. Since the drying process of the manure according to the present invention takes place more quickly than in the situation wherein only the air present on the upper side of the conveyor belt is used for drying, the emission of ammonia to the outside air in such a multi-level accommodation system for broilers according to the present invention will be lower. Another advantage is the fact that no exchange of air flows can take place between the vertically adjacent levels, because the impermeable part of the conveyor belt on each level functions as a so-called dividing plate between the levels. In an embodiment of this type a fresh amount of air is used for drying on each level .

In a preferred embodiment of the multi-level accommodation system for broilers according to the present invention said means for supplying air comprises a system of pipes, which system of pipes is disposed in such a manner that air is supplied to a space present between the air permeable part of the conveyor belt and the impermeable

part thereof. The system of pipes may be provided in the form of separate pipes extending along the conveyor belt, but in certain embodiments it is preferred for the system of pipes to form a part of the level structure.

Furthermore it is preferred to provide the level with additional blowing means, which blowing means is mounted in the space above the conveyor belt. Such a blowing means provides an additional air flow above the conveyor belt on which the broilers are present. Since the broilers present on the conveyor belt by nature tend to sit together in one place, the conveyor belt is provided with regularly spaced-apart partitions or baffles. In this manner separate living spaces for broilers are created on the conveyor belt. Preferably such partitions, which are disposed slightly transversely to the conveyor belt, are air permeable so as not to impede the transport of air above the conveyor belt. With a view to enhancing the well-being of the broilers and contributing to the drying process of the manure it is furthermore preferred to place wood shavings, sawdust or another soft and moisture-absorbing material on the conveyor belt.

In a preferred embodiment of the multi-level accommodation system according to the present invention the position of the conveyor belt during the fattening period of the broilers is set such that the broilers are present on the air permeable part of the conveyor belt. The endless conveyor belt according to the present invention is preferably made of woven natural or synthetic fibres, in particular polyester fibres, polypropylene fibres, polyethylene fibres or ara id (trademark) fibres. Fibres of the above types are sufficiently strong and resistant against the acidic excreta from the animals to be used as a conveyor belt. It is preferred to provide perforations in the air permeable part of the endless conveyor belt. It should be understood, however, that such perforations must be dimensioned such that the material to be dried will remain on the conveyor belt, whilst the air flow being supplied on the bottom side of the conveyor belt can pass through the perforations. It is preferred to provide the part of the conveyor belt that is not permeable to air with a coating, which prevents air from passing through the conveyor belt. It is also possible, however, to weave or interconnect the fibres of the conveyor belt in such a manner that the conveyor belt is formed with a part which is permeable to air and with a part which is impermeable to air. Furthermore it is possible to manufacture the conveyor

belt as a whole of a polymeric material, preferably polypropylene. A belt of this kind is for example obtained by supplying the polymeric starting material to a rolling apparatus, so that a thin foil is formed. The foil is subsequently provided with perforations, which perforations can be made impermeable to air by the application of a coating.

The multi-level accommodation system for broilers according to the present invention is preferably designed such that it is possible to regulate the amount of air from the means for supplying air that is to be supplied to a level. Said regulating of the amount of air to be supplied preferably takes place by providing the level on the air supply side thereof with a movable element, which is capable of closing off the air supply side of said level. A screen, for example a vertically or horizontally movable curtain, is a suitable movable element. Because the broilers present on the conveyor belt develop a certain amount of heat themselves and consume oxygen, it is advisable to exhaust the amount of heat that is produced in a controlled manner, whereby the amount of oxygen that is needed for the broilers must be taken into consideration, of course. In wintery conditions the temperature of the cold outside air, which air may be supplied to the multi-level accommodation system according to the present invention, may provide too much cooling for the animals present on the respective level at a particular air supply velocity, so that it may become desirable to reduce the amount of air to be supplied to said level . Said reducing of the amount of air to be suppl ied to a level takes place in that the movable screen closes off part of the air supply side of the level . In summery conditions, wherein a considerable exhaustion of heat from the level is exactly what is needed, the movable element may leave the air supply side of the respective level practically entirely open, thus creating a situation where the exhaustion of heat from the level is optimal. It is preferred to provide each level with a movable screen, whereby the screens can be controlled independently of each other.

According to the invention the movable element to be used for regulating the amount of air to be supplied to the level is preferably connected to a regulating and control unit comprising means for measuring the temperature and/or the air humidity. Said means for measuring the temperature and/or the air humidity is in particular disposed at such a position on the respective level that a temperature value and/or an air humidity value which is characteristic of said level is measured.

Such a position on the level is for example the point which forms the centre of the conveyor belt, but any other position for measuring the temperature and/or the air humidity is also possible. If the means for measuring the temperature and/or the air humidity is disposed at a short distance from the air supply side, the temperature and/or the air humidity halfway the conveyor belt will fall short of the desired value, however.

More in particular, each level comprises two individually controllable screens, whereby the first screen closes off the air supply side above the conveyor belt and the second screen closes off the air supply side under the conveyor belt. According to a similar embodiment the amount of air above the conveyor belt, which amount in particular determines the well-being of the animals, can be regulated independently of the amount of air under the conveyor belt, which amount of air in particular serves to dry the manure present on the conveyor belt. The present invention furthermore relates to a method for accommodating broilers by using the multi-level accommodation system for broilers according to the present invention. The method according to the present invention is characterized in that the broilers are accommodated on the air permeable part of the conveyor belt, which part may be provided with wood shavings, wherein the amount of air to be supplied to the broilers is regulated by the first screen and the amount of air to be supplied to the conveyor belt may be regulated by the second screen, and wherein, after a selected accommodation period has elapsed, the conveyor belt is driven following the removal of the partitions from the conveyor belt, whereby the broilers and the material present on the conveyor belt are carried off. Thus the function of the conveyor belt is threefold. On the one hand the conveyor belt provides a place for the animals to sit and scratch about, whereby the manure is at the same time dried. On the other hand the conveyor belt functions as a means of conveyance, by which the broilers and the manure can be removed. In addition to that the special construction of the conveyor belt prevents the air flows of the various levels from being mixed.

Preferably the air from a stable is used as the air flow to be supplied to each level. In order to achieve an optimal drying effect and an optimal environment for the animals it is preferred, however, for the air temperature to be at least 10 ^' C. It is also possible, however, to use outside air or a mixture of outside air and stable air. In addition

to that it is possible to subject the air to be supplied to a pre-treat ent step, for example heating, cooling, drying, etc.

The multi-level accommodation system for broilers according to the present invention will be explained in more detail in the accompanying Figures.

Figure 1 is a diagrammatic front view of the multi-level accommodation system for broilers according to the present invention.

Figure 2 is a diagrammatic plan view of the multi-level accommodation system for broilers according to the present invention shown in Figure 1.

Figure 3 is a larger-scale, diagrammatic front view of the multi-level accommodation system for broilers according to the present invention.

Figure 4 is a larger-scale, diagrammatic front view of the multi-level accommodation system for broilers according to a special embodiment of the present invention.

Figure 1 shows in stable 1 a multi-level accommodation system 5 for broilers according to the present invention. Multi-level accommodation system 5 for broilers is built up of a number of levels 6, 7, 8, 9, 10. The supply of air to each multi-level accommodation system

5 takes place by means of air supply means 2, whereby the air is subsequently exhausted from stable 1 via air exhaust means 3. The air supplied via air supply means 2 is supplied via passage 29 to the space under the conveyor belt as well as to the space above the conveyor belt for each individual level 6, 7, 8, 9, 10. The air then exits stable 1 via air exhaust means 3. Present on each level 6, 7, 8, 9, 10 are broilers and nipple drinkers 11 and feed pans 12. Although the multi-level accommodation system 5 shown in Figure 1 is built up of five levels 6,

7, 8, 9, 10, it is to be understood that the present invention is not limited to a specific number of levels.

Figure 2 is a diagrammatic plan view of the multi-level accommodation system 5 for broilers that is shown in Figure 1. Each level is provided with an endless conveyor belt 15, which comprises a part which is permeable to air and a part which is impermeable to air. Endless conveyor belt 15 extends along the entire length of each level and is driven by drive unit 16. With a view to the well-being of the animals, the space on conveyor belt 15 is subdivided into separate accommodation

or living spaces by partitions 13. This makes it possible to keep the amount of broilers per square metre constant and prevents situations where all the broilers are present on a particular part of conveyor belt 15. In addition to that each accommodation space is provided with nipple drinkers 11 and feed pans 12. Air exhaust means 3 are present between the various multi-level accommodation systems 5. The air supply means are indicated at reference number 2. After the broilers have been accommodated on conveyor belt 15 for a selected period of time, partitions 13 are removed and conveyor belt 15 is driven by means of drive unit 16. The feeding system for feed pans 12 is indicated at reference number 14. The broilers and the dried manure and wood shavings present on conveyor belt 15 are subsequently carried off. Then conveyor belt 15 is cleaned and the air permeable part of the conveyor belt is positioned in such a manner that a new amount of broilers can be accommodated on the air permeable part of the conveyor belt. In this manner a new fattening or accommodation period is started.

Figure 3 is a larger-scale, diagrammatic front view of the multi-level accommodation system 5 for broilers according to the present invention. For the sake of clarity only one multi-level accommodation system 5 is shown, which system comprises three levels, namely levels 6, 7, 8. It should be understood, however, that the present invention is by no means limited to a specific number of levels. Air is supplied to multi-level accommodation system 5 via air supply means 2. During the accommodation period of the broilers conveyor belt 15 occupies such a position that air permeable part 25 on level 6 forms the base on which the broilers are present, and the air impermeable part 22 of conveyor belt 15 thus forms a partition between level 6 and level 7. Numeral 28 indicates a support for conveyor belt 15. The air coming from air supply means 2 is supplied to level 6 both above and under conveyor belt 15. Movable screen 19, which is provided on the air supply side of level 6, is positioned in such a manner that air from air supply means 2 can flow under conveyor belt 15 as well as along the broilers present on conveyor belt 15 without any impediment, after which the air exits level 6. The amount of air to be supplied to level 7 is limited to a considerable degree because movable screen 20 closes off a part of the air supply side above the conveyor belt of level 7. On level 7 the air from air supply means 2 is divided into an amount of air under the conveyor belt and an amount

of air above the conveyor belt, whereby it should be noted that the air of level 7 cannot come into contact with the air of level 6 as a result of the presence of the air impermeable part 22 of conveyor belt 15 on level 6. Level 8 shows the situation wherein movable screen 21 almost completely closes off the air supply side above the conveyor belt of level 8. In this manner air from air supply means 2 can only enter level 8 via the bottom side of conveyor belt 15. The air impermeable part 24 of conveyor belt 15 ensures that the incoming air enters level 8 via the air permeable part 27 of conveyor belt 15. As is shown in Figure 3, movable screen 19 on level 6 closes off the air supply side above the conveyor belt to a very limited extent, and movable screen 21 closes off the air supply side above the conveyor belt of level 8 practically completely but the present invention is by no means limited to such a position of movable screens 19, 21. After all it is possible to position movable screens 19, 20, 21 independently of each other. In one embodiment of the present invention (not shown) it is also possible to regulate the amount of air to be supplied at the bottom side of the conveyor belt. Thus a movable screen may be provided, which screen is capable of closing off the air supply side at the bottom side of the conveyor belt. In this manner it is possible to provide each level with two screens, which may be individually controllable, for supplying air in a controlled manner.

Figure 4 is a larger-scale, diagrammatic front view of a special embodiment of the present invention. Multi-level accommodation system 5 is provided on both longitudinal sides thereof with a system of pipes 31. Said system of pipes 31 provides for air to be supplied to each level 6, 7, 8, to the space which is formed between the air permeable part and the air impermeable part of conveyor belt 15, said space being formed, on level 6, for example, by air impermeable part 22 and air permeable part 25 of conveyor belt 15. In order to achieve a proper air flow above the conveyor belt it is possible to provide levels 6, 7, 8 with an additional blowing means 30. Although Figure 4 shows air being supplied via air supply means 2 as well, it is preferred in some embodiments to use only blowing means 30 and/or system of pipes 31. In addition to that the multi-level accommodation system 5 shown in said Figure 4 is not limited by the presence and/or the position of movable screens 19, 20, 21. In certain embodiments it is desirable not to use movable screens 19, 20, 21 and to regulate the amount of air via system of pipes 31 and/or blowing means 30.