Flemish rabbits can grow quite large, can reach about 20-22 lbs., and especially need a good size cage when expecting a litter. These rabbits don't like the heat and should be kept out of the sun and taken indoors when the temperature is over 90 degrees. A covered floor for the cage such as plywood gives the rabbit a comfortable place to lie on and has the advantage of being easy to clean as it lifts out. The best age to begin breeding a Flemish rabbit is 9 months. They give birth after 30-32 days usually. Litters can be anywhere from 5-12 babies. It's best if they have no more litters after the age of three years old.