Its all about expending energy, pigeons regulate their temperature by opening/closing their feathers so this crap about making them tough by keeping them in an aviary is nonsense.Have you ever been in a loft when its minus 10degrees, the birds look perfect.Therefore the cold doesnt affect them BUT it does burn up energy, hence them eating like fk in the winter.Thats why it is advisable, but not essential, to make them as comfy as poss after a race to aid recovery and SAVE ENERGY.