Thank you all for your thoughts! I spoke with a public health nurse who agreed with my inclination to keep the healthy sibling home. While a daycare centre would not require this, in a home daycare the impact of me or my children getting sick is very different (I can't call in sick and have someone cover me and care for my group of kids). I also read some other forums and it seems that providers are divided 50-50 on whether to allow healthy siblings, so I guess like so many other things we stand for what feels best for us. Now to get through the week without anyone else catching the bug...