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Breeding control in ferrets

The problem with Jills

Jills (female ferrets) usually come into season in the spring and will remain in season until they are mated. If they are not mated (as they would be in the natural situation) the constant high oestrogen levels will eventually stop their bone marrow producing new blood cells and they become seriously ill. There are four ways round this:

Breeding: This may not be a good solution if you do not have ready homes for ferrets.

Speying: Requires an anaesthetic and surgery, but this is a low-risk procedure.

Injection: A hormonal injection (often referred to as a "Jill jab") will stop the season and usually only needs to be given once a year.

A vasectomised male: Select a male to be vasectomised (see below). He can the stop the season by mating without the risk of unwanted kits.


Speying Jills can be performed from 5 months of age. The uterus and ovaries and removed through a mid-line incision under a general anaesthetic.

Following a spey, a Jill will need to be kept indoors for 24 hours until the anaesthetic after effects are over.


Choose a male in good health with a healthy pair of testicles. You want him to be fairly robust so that he will act in a dominant enough manner to mate the Jills. It is best to wait until 9-12 months of age to perform the procedure to ensure he will be suitable and is fully mature.

The procedure involves cutting and tying off the vas deferens (the tube from the testicles) through two small incisions in the groin. This leaves the testicles, and therefore the sexual drive, intact. A general anaesthetic will be required.

You should wait at least 6 weeks before introducing him to the females as there could still be viable sperm present for this time. 


This is a fairly minor procedure involving the removal of the testicles through two small incisions in the scrotum under a general anaesthetic.

Castration may be a useful procedure to help breeding control in ferrets. It may also reduce their odour (but not eliminate it) and may make them calmer to handle.

Castration can be performed as soon as the testicles are fully descended, usually from 5 months of age.