The animal an antibody is raised in decides more than its price. It sets which secondary antibodies you can use, whether the antibody will cross-react with your sample, how much of it you get, and which detection formats it suits. A quick tour of the common hosts and when each one is the right call.
Polyclonal hosts
Rabbit is the default polyclonal host, and for good reason. Rabbits mount a strong, high-affinity response to a wide range of antigens, including peptides and proteins that are poorly immunogenic in rodents, and a single animal gives tens of milliliters of serum per bleed. Rabbit IgG binds Protein A well, so purification is straightforward, and you can get an anti-rabbit secondary in any label you like. Most of our neuroscience antibodies are rabbit polyclonals for exactly these reasons.
Sheep and goat give far larger serum volumes, which matters when the antibody is going to be a bulk reagent. They also give you a second species for double labelling alongside a rabbit or mouse antibody against another target. We raise sheep versions of several of our rabbit antibodies for that purpose.
Chicken antibodies (IgY) are phylogenetically distant from mammalian IgG, so they don't bind mammalian Fc receptors or Protein A/G and are less likely to cross-react with mammalian proteins in the sample. They're collected from egg yolk rather than blood, which suits some animal-welfare policies, but the secondary and purification toolkits are thinner.
Monoclonal hosts
Mouse hybridomas are the standard route to a monoclonal. The methods are mature, mouse isotype controls and secondaries are everywhere, and most clinical and research monoclonals started in mice. The problem comes when the sample is mouse tissue, because an anti-mouse secondary lights up the endogenous immunoglobulin. A rabbit or rat antibody is easier to use on mouse samples.
Rat monoclonals fill that gap and are the usual choice for antibodies against mouse proteins, since mice tolerate rat epitopes poorly and rats respond well to mouse antigens. Hamster is a niche host for some anti-mouse targets that neither rats nor mice respond to. Rabbit monoclonals combine rabbit affinity with clonal consistency and are increasingly common, although production is more specialized.
Matching the host to the experiment
Start with the sample: if it's mouse tissue, avoid a mouse primary; if it's human tissue, most hosts are fine. Then count the antibodies you'll use together. Each needs a distinct host, or the secondaries will cross-detect. Think about the format next: polyclonals give stronger signal in Western blot and IHC, while monoclonals give the reproducibility a diagnostic or a long project needs. After that the choice is practical. Rabbit for affinity and convenience, sheep or goat for volume, chicken when mammalian cross-reactivity is the problem you're trying to get around.
Because we raise antibodies in rabbit, sheep and mouse, several of our targets come in more than one species, rabbit and sheep tyrosine hydroxylase among them, so you can co-stain without a secondary conflict. If you need a target in a host we don't list, ask about custom production.