Cold weather

How do you keep your rabbits warm during this cold spell, been feeding them black oil sunflower seeds , insulated and put heat lamp in their hutch . They seem to be doing OK but Im still worried about them

Never had a problem with the cold as long as they are sheltered from the wind and have good dry bedding, other than the water.

Thanks , they dont seem to be having a problem with the cold .Glad I put 1/2" foam insulation around their hutch .

"Glad I put 1/2" foam insulation around their hutch"

I really hope you put it out of their reach, because if they can reach it , they will eat it. From when I did research on and for a short while raised meat
rabbits, I found as long as they had a roof over head, to keep out rain and some shielding from the wind, they were fine. Most rabbits tend to love the cold,
it's the heat you have to worry about. If you are still worried you could get them a small box and fill with hay. I use to use the ones the half gallon juice
containers came in, 6 to a box. Save-a-lot and Aldis stores usually have alot of those types for the taking. Yes they will eat the hay, but you want to give
them that anyway. And yes they will chew/eat the box, but mine usually took a week or longer to do so, and I was going shopping on a weekly basis, so no
biggy. Some actually left the boxes alone, but I would still replace them bi-weekly anyway, as they deficated in them .

I keep my rabbits in a 3 sided shelter with an angled roof that faces open to the south. Inside there are 2 hanging wire cages. They are sheltered from the prevailing winds and even cold down to -20F hasn't seemed to bother them. On really cold and windy spells I pack a lot of hay in the cages so that they can make their own shelters. They have nice dry platforms to rest their hocks and plenty of food and water. So far so good. The doe even had a litter of six on a night that was -10F. That whole first week was bitterly cold. They survived and at eight weeks of age they were around 5.5 pounds each. Five of the six have been put into the fridge and I'll be re breeding the doe soon.

As long as they can get out of the wind... they are good.
The trouble with a heat lamp is that if they get used to having it, they won't develop cold tolerance. If for some reason you lose power or the bulbs blows out overnight, you could wake up to dead rabbits. It's best to breed for cold hardy rabbits rather than investing in infrastructure to support weak animals. That's just me though.

Built them a hutch with 4 hanging cages , guess its more of a rabbit house ,it was open but I put the foam boards up around the frame away from the rabbits , have had them for two years now theve always done well in the cold ,but last week we dropped to -30 at night , they made it thru good , turned the lights off as soon as the weather got above -10.

In my experience rabbits are extremely cold hardy animals, and they'll do just fine in a sheltered hutch with a good bed of straw. I have three that've been doing great through our cold winter with no heat lamps or heat sources of any kind. We've had several week long cold snaps down to -35C/-31F (down to -47C/-52F with windchill). The rabbits are thriving, and it's all their first winter. Two come from some pretty hardy stock, with the other coming from a rabbit factory farm setting which never bred for winter hardiness.
I surrounded the hutch with flax straw, and put in a good deep layer (6-8 inches) of wheat straw inside for them. They also each have access to a south facing window for solar heat. My insulation isn't very thick, nor are the cages draft proof (for ventilation purposes). The rabbits are healthy with no signs of frostbitten ears, or any other exposure problems.
A friend of mine (who I got the hardy stock from) has rabbits in this same set up, with no heat sources beyond their collective body heat and the sun. Two of her rabbits just gave birth this week, and all the babies survived and are doing fine.
In my opinion, I don't think rabbits ever need supplemental heating sources as long as they are sheltered from the wind, and can get the sun as a heat source. I also think Craig Dobbelyu is right about the risks of heat source failure. Just my two cents. Cheers!

Rabbits have more of a problem with heat than cold. -20 is nothing for a rabbit that is housed outdoors year round as long as they have a place to get out of the wind. Here I can't breed in summer because it's too hot for does to be pregnant so, I breed in winter and, even at 15, no problem for the kits (assuming the doe made a good nest of course.)

Heat, now that is another matter, anything above 80 and, your rabbit is in danger of heat stroke so, needs ways to keep cool. A frozen 1 liter bottle of water, ice in a dish of water to drink, frozen fruit snacks, vegetable juice ice cubes, a mister and a fan, anything to keep them cool.

Mine are free around the house! When we got snow first time, they were playing like little kids in snow! Jumping and running around, they also made tunnels!

No problem with cold for an older than ~2 monts rabbit, even in -40f temps.

They need a bit more, and better food, a dry place with hey or straw, and no wind. Water will freeze, so it's necessary fresh water every day. They may start eating snow, like mine do, but fresh liquid water is better.