[SKB_Hamsters]

Yes this is true - I am not a breeder myself from what I have read before on the forum it has something to do with the light intensity/levels in winter months being lower which can cause a female hamster not to come into heat or be less fertile if she does go into heat

Like cypher has mentioned it due to natural instincts too as hamsters haven't been domesticated for as long as other common pets so still rely a lot on natural instincts - in the wild hamsters would also hibernate in the winter months therefore wont want to conceive as the survival of both the mother and pups would be affected by the harsh winter weather although domesticated hamsters don't hibernate this natural behaviour may still be present in our domesticated hamsters.