Outdoor buns- when to put back out?

Hey,

I have a couple of outdoor buns who were bought in around 4 weeks ago due to one having an infection and the Vet advising us to keep him in. As it has been so cold they have remained in doors while his antibiotics are finished etc. He seems ok in himself now, but as it is still so cold and they have been in doors now for nearly a month, I am concerned about putting them back outside now they are used to the warm.
They have been out in their run during the day however they have been huddling in the corner.
I have turned the heater off where they are so they start getting a bit used to the cold again.
Should I wait to put them back out until the weather picks up? if so what temp do you think would be good?

my rabbit has been hideing in her den and her hutch most of the day (she can be lazzy tho:lol i think its the wind i put extra hay in and a hot water bottle, at night i make her hutch out to be a under ground burrow to try and make it warmer she always looks snug on a morrning

i would try putting them out if you fink they miss it, if they dont why rush

We bring Ron and ginny into the garage (no heating) when the clocks change in October, that way they have access to the whole garage as they only come out into the garden during the winter months at the weekends for an hour or so. But we bring them back outside when the clocks change in March as they have more access to the garden during daylight.