When choosing an animal to generate polyclonal antibodies, you need to consider these three factors: 

• The amount of antibody required
• The antibody characteristic - class and isotype
• The immune response – for a stronger immune response you need to use phylogenetically distant animals as the antigen donor 

When you need a large quantity of antisera, consider using goats and horses.

The immune response of chickens can be stronger as they are phylogenetically distant from mammals such as mice and humans. An advantage of using chickens is that the immunoglobulins are transferred into the egg yolk, which renders the invasive bleeding procedure unnecessary as Abs can be harvested directly from the eggs.