IgG
Mammalian, polyclonal antibodies can precipiate following affinity purification. This can happed directly afterwards or overnight during cold storage. Some antigens will stimulate a production of a class of IgG which is called a cryoglobulins, what means that they will precipitate in a cold. However, warming up to room temperature can solve this problem. Antibody solution can be also centrifuged to remove precipitates.
IgY
Chicken antibodies can also precipitate when stored in the cold overnight or after several weeks. Warming up to room temperature often helps to dissolve those precipitates. Otherwise, IgY solution can be centrifuged to remove precipitation prior to use.
Antibody solutions stored without preservatives are in risk to be contaminated by bacterial growth, which is often most common reason for protein inactivation.
In case of questions - you are welcome to contact me directly:
joanna@agrisera.se