Winter Litters

October gets to be that time of year in the Northern Hemisphere when the nights get colder and sometimes the days don’t get much warmer than the nights. I've been raising Rex for over 20 years and I didn't used to breed in the winter but I've had occasional litters in the past when the temperatures were well below freezing - usually they do fine. I've had a few does lose singleton babies when it was 40 below but I rarely loose babies to the cold.

In 2010 I tried breeding year round for the first time. My rabbits live in an unheated garage during the winter and I don't use extra heat. I live far enough in the country that if a fire were to start anywhere I'd have almost no hope of saving anything. As a result I really hate using heat lamps and try to avoid them whenever possible. The only time I ever I hung a heat lamp above a nest box I ended up losing the whole litter. It was in the minus teens and when I checked on a just born litter the nest fur was crusty on the outside - the moisture from the babies breathing must have condensed and then frozen. I felt sorry for them (even though they were toasty warm when I put my hand in the nest) so I hung a heat lamp about 12 inches above the nest. When I came back 2 hours later they were all dead. The lesson I learned: I should have trusted their mom and left them alone.

I know many people fret when the temperatures drop below freezing, but if you take some precautions, you don’t have to suffer losses to the cold. Use nest boxes made out of material that insulates and make sure your does have plenty of nesting material.

I use either wooden nest boxes with lids or plastic storage bins (about 18“ x 12” x 8“ high) with a 6” hole cut in one side and the lid on (see the photos on the housing page). I set that on top of a piece of plywood so there are several layers of something between the babies and the cage wire. Remember that babies wiggling around will often end up on the bare floor of the nestbox so it’s important that that not be metal. My nest boxes are big enough that the does can sit inside next to the babies without sitting on them. Many of my does sit near the babies when it's really cold. I make sure the does have plenty of straw for bedding.

The cold will usually not be a problem if the doe has been able to make a good nest. I give them as much hay or straw as they can stuff into the nest box, and rabbit fur is a VERY good insulator. I live in Alberta Canada where it can get really cold and this past winter was bitterly cold. In 2010/2011 I had litters born Dec. 8, 25, Jan 12, and Mar 6. They were in an UNheated garage. Like I said above, I have two different kinds of nest boxes and both are covered. One is a wooden box that is open on one end but has a 4“ high board across the lower part. The other is a plastic storage bin with the lid on and a 6” hole cut at the end of one side. I usually put some plywood underneath the nest box and when I take the box out to check babies that board is often warm underneath where the babies are. I also try and make sure none of the hay in the nest gets flattened down and that the doe's fur is carefully arranged over the babies after I've checked them. I check them daily for the first 4-5 days, then every other day after that. I often take them out to photograph them but if it's really cold I just count them without picking them up. When the first December litters were born, the temps were around freezing during the day and -14 or so at night. There were days when it was much colder. We even had a few nights where it dipped below -20.

I also think it helps if the litters are big enough (6-8) to keep each other warm, and it also helps if the weather cooperates so that it isn't bitterly cold (i.e. below zero) until the babies have some fur, but that only takes a few days.

I was worried about one of the litters born January 8 because one doe was a first-time mom who only had 4 kits and it was VERY cold. One baby was quite chilled when I found them, so I heated it under my coat for a while and put it back. When I checked an hour later, it was cold again so I took the nestbox in the house and put a fan heater on it for about an hour. Then I wrapped the whole box in an old sheet (except for a space for the doe to get in an out) and took it back outside. The baby who got chilled was also smaller than the rest so I kind of expected to lose it. The week they were born was bitterly cold: lows around -10F and highs around 0F. The weather was all over the map this past winter - going as high as 60F and as low as -20F. At four weeks those four kits were the hoppiest and most playful babies I've had in a very long time. The one that got chilled is the silliest of the bunch.

Of the 10 litters I had in 2010/2011 winter, with one exception, the only babies I lost were to first time moms, and none of them lost more than I would expect to lose at any other time of the year. I did lose one baby that ended up outside the nestbox. If it had been summer, it still would have died.

I try to keep my stock strong and healthy, and as natural as possible. Good mothering ability is something we can select for. I think does that can't or won't look after their babies properly should probably be replaced. For me that includes being able to raise litters in the winter without heat.

Update 2015: I have since upgraded the space in my still unheated garage and have room for a few more rabbits as well as a few growing pens. I've been breeding year-round since 2010, and the only time I lose any babies to the cold is when they end up outside the nest box, or the doe scatters them (sometimes first-time moms will do that).

I now hang as many as 4 heat lamps to increase the ambient temperature and now my water bottles hardly ever freeze. Only when the outside temps are colder than 15 below C (about 0F) for more than a day do I have to worry about water bottles freezing. I have a duplicate set of water bottles for when that happens so I can just go and switch the frozen bottle for fresh ones twice a day. I bring the frozen ones in the house, and unless it's really cold (like 30 below), they will be thawed by the time I want to switch them again.

Update 2020: Thought it was time to report on some of the changes relevant to winter litters in the last 5 years.

I no longer use ANY heat lamps.
I have instead added 2 fans: 1 that is always on. It is situated about 4 feet from a window that is open a crack year-round (except during storms). The second is on timer along with my lights in the winter (in summer, it is always on too). Among other things, the airflow helps to keep the temperature consistent throughout the rabbitry.
I have also added 2 heaters - one is a small ceramic heater, placed right by the open window. It is on when the daily temperatures fall below -10C. The other is a larger, wood cabinet heater, placed on the floor near the window & door. I turn it on when I'm outside working and when the outside temps drop below -15. I vacuum away fur and debris from both the fans and the heaters on a regular basis.
Finally, I have replaced most of the lights in the rabbitry with LED lights. The overhead lights are 4' shop lights, at 18 watts each. The cages have LED lights around and in the cages on timers to extend the daylight from about 8AM to 10PM (they are off during the day as I have some natural light from 2 windows.
For what it's worth: I had 3 litters born on Dec 3/2020 out of 5 does bred totaling 28 kits (9, 11, 8), 3 litters born Christmas Eve out of 4 does bred totaling 26 kits (9, 6, 11), and I have 6 does due Jan. 14/21.
Out of the 54 live kits born in December, we lost only 1.