Yes, they are much smaller so unable to retain heat like other breeds. I would go by their behavior. If they still seem cold at 90 then I would raise to 95. They shouldn't need warmer than that at 3 weeks old.I was wondering if Seramas are usually brooded at a higher temperature. I bought two 3 week olds and they seem to be cold at 85 degrees so I raised the temp. to around 90. They still stay cuddled up under the heat lamp. I'm wondering if it may have something to do with the blood draw they had to be sold at a show or if it's just that these little ones need more heat?