Polyclonal antibodies are conventionally obtained by the time consuming method of immunizing a suitable host, usually a mammalian animal, with a composition comprising the molecule of interest as an antigen and a suitable adjuvant. The antibody may be e.g. a chemical compound or a peptide where the latter may be chosen from a peptide library containing a great number of peptides having a systematic combination of amino acids.
Several weeks subsequent to immunization, antibodies generated by several B cell clones, hence the term polyclonal, specific to the antigen can be harvested by bleeding the animal and collecting the serum. Polyclonal antibodies may bind different parts of the antigen although individual polyclonal antibodies may bind virtually the same parts of an antigen with different affinities.
Polyclonal antibodies are typically obtained from mammalian host animals such as rats, mice, goats, horses, sheep, rabbits, pigs and others. A large amount of experimental animals are used to generate different antibodies—one animal is used per antigen. The animal will experience discomfort associated with the immunization and in particular the bleeding procedures. It is expensive and laborious to obtain antibodies specific to a large number of different antigens, since a similar large amount of animals is required.
On one occasion however, the possibility of immunizing individual animals with more than one antigen has been discussed in connection with a semi-automated method of hybridoma generation using mice immunized with multiple antigens and a novel antigen microarray assay (Proteomics 5: 4070-4081, 2005 and WO 03089471). In this document, mice were immunized with 10 μg of 5-10 different protein antigens having sizes ranging from about 12 to about 48 kDa in order to solve the bottleneck problem in providing monoclonal antibodies to proteins encoded by the human genome. In the discussion of the scientific paper it is stated that “It is also possible that increasing the number of immunogens for each animal may ultimately lower the number of positive clones in any one fusion. Indeed, subsequent production runs within our laboratory have shown that five antigens per animal are optimal”. A major problem associated with immunizing with more than one antigen is, according to WO 03089471, immunodominance. In order to circumvent this problem, the animal was injected with several antigen boosters. Immunization with more than one antigen is not recommended, apart from perhaps in special cases involving automated procedures for generating mice monoclonal hybridoma B cell lines, in which case it is recommended to immunize with no more than 5-10 different purified protein antigens. In the patent application it is also suggested that that immunization might be carried out with up to 50 different antigens. However, no specific examples demonstrate that this approach will work with a reasonable expectation of success.
Conventionally obtained antibodies have several other drawbacks in addition to being relatively expensive and time consuming to produce. It may e.g. be difficult to obtain a sufficient response toward mammalian antigens. In general, the large degree of conservation of immunoglobulin structure, immunoglobulin receptor structures, etc. among mammals does in many cases give rise to inaccurate test results when using mammalian antibodies for e.g. detecting mammalian antigens. Also, the problems with protein A/protein G binding, interference with rheumatoid factor, and activation of mammalian complement are often encountered when using mammalian antibodies and mammalian antigens.
In The FASEB Journal 4:2528-2532, 2001 it is disclosed that by immunizing a chicken during a 20 day period with a total amount of about 30-300 μg antigen, an immune response could be detected about 2-3 weeks later. It is concluded that the egg yolk is a convenient source of polyclonal antibodies because:                the quantity of antigen needed is much lower compared to rabbits,        birds produce antibodies against highly conserved mammalian antigens,        the use of complete Freunds adjuvant leads to very high and long lasting titers of yolk antibodies, starting as early as 16 days after the first immunization,        the purification of antibodies is simple and quick, and a purity of 90% is easily attained by PEG precipitation,        chicken are inexpensive to keep and easy to handle,        chicken antibodies are acid- and heat-resistant and therefore might be orally applied to prevent or to cure intestinal diseases of young animals or humans.The document does not however, discuss if specific antibodies can be generated in a much faster and much more inexpensive way.        
It is thus known that a number of advantages are associated with obtaining antibodies in a non-invasive way from eggs from an immunized chicken rather than collecting blood from an immunized mammal. However, the time required for generating antibodies is not dramatically reduced when using hen/chicken antibodies. And also, a large amount of birds are used to generate antibodies in cases where a large amount of different antigens are used. The available literature in this field does not provide any suggestions for providing specific antibodies in a dramatically faster and more inexpensive way.
In Handbook of Laboratory Animal Science, Second Edition, Vol 1, Jann Hau e.g. it is disclosed that “For each antigen, there is a dose called the “window of immunogenicity.” Too much or too little antigen may induce suppression, sensitization, tolerance, or other unwanted immunomodulation7. Very low doses (<1 to 5 μg) are used to induce hypersensitivity (allergy) and should be avoided in immunization of animals, particularly because booster injections may result in anaphylactic shock in the animals.”
There exists a dogma within the field of immunology that repeated immunizations with low doses of allergen may result in anaphylactic shock and that it is not possible to immunize animals with a large amount of antigens.