My pups are now 8 days old and so far doing well. Although I have a heat lamp in place, I have once again used my heat mat and not the lamp. The only thing is that sometimes I have thought they are not as warm as I would like them and I cannot feel any/much heat on the vet bed and it almost seems too thick for any heat to come through to them. They are in a centrally heated room, free from draught. So a couple of times I have switched the heat lamp on for a while to really warm them.
I know it will not be that much longer before they start regulating their heat but finding it hard to get the balance right between too warm and not warm enough. I am using a freedom pen for the first time but we have lined the walls with corrugated plastic sheets as we were concerned they would get through either wholly or with limbs. Also helps to keep privacy for Mum and draughts. She has her own room.
We do have to keep checking that she hasn't moved them away from the mat as she prefers to lie with them away from the mat. She isn't in there with them all the time now but seems to go in when they start up with noise. There are 10 of them but it is when one gets separated.
Just wondered what others do to make certain they maintain a certain temperature.

I usually put a metal or vinyl electric heat pad on top of the vetbed in one front corner of the whelping box. So it only takes up about a sixth of the whelping box space. Cover the pad in a sealed simulated fur cover. Take great care where the electric cable runs. Then the mother doesn't have to lay on the heat pad and the puppies will all move on to it if they are not warm enough.

Ah so you put the mat on top. It has a fleece cover on it and is only a small area of the box. I'll do that instead. As I say when they are together as a group and with Mum they seem OK but have found a few times a pup spread out on its own after she has got up and that is when I have thought they were not so warm. Not chilled as the heating is on but just not as warm to the feel as I would like.

You say that mum has her own room.  Is this away from you?  Or are you with them all the time?

We have always used a brood lamp, leaving a thermometer on one of the pig rails round the side to check the heat level down there.   I have to admit that in order to get it warm enough at that level, I have noticed my bitches appearing to get too hot - and for this we drape a sheet across the back end of the box, so she has somewhere to get out from directly under the lamp, without losing the benefit to the litter of the lamp.   This has always works, for us.

We work from a room adjoining the whelping room and have spent the last 8 days more or less there or in with her. At the age of the puppies now I have never had a bitch who wants to be with the pups all the time so she goes in when she needs and wants to. She has been one of my best Mum's to date.