I'm having a problem with our dogs because they've recently started using my kitchen as a toilet during the nights, this is unusual behaviour for them because they're normally very clean.  It's been going on for the last couple of weeks and I'm wondering if it's related to one of my dogs being in season, although it's never occured before during seasons.
I haven't yet managed to discover if it's both dogs who are doing this or if it's just one of them because they both look very sheepish when I come down and discover the mess in the morning!
They are both bitches, one is six years old and the other is four years old, the younger of the two is currently in season and I'm more inclined to think that she is the one whose responsible for the morning messes.  They always go out to toilet before I tuck them into their bed and I'm up early in the mornings so they're only left for around 7 hours during the night.
On Monday evening I had to leave them for 1 hour while I  picked my kids up,I made the dogs go out to toilet before I left the house, and when I returned home an hour later there was a horrible mess!  and there was a mess again when I got up on Tuesday morning, same again this morning.
Please help, my stomach tends to be a bit delicate in the mornings, and it's not the most appealing thing to open the kitchen door to at six o'clock in the morning is it!!  and I'm worried my house is going to stink if this keeps happening

Your advice would be greatly appreciated
Thanks
Mair

There can be many reasons for this happening. The first being obvious. The bitch is in season! However, there could be other reasons. So, by trying to eliminate any reasons lets go through a few others (hope I don't sound like a school marm ;) )

When do you give them their last meal? A change of timing might stop it.

Have you given them anything different to eat? and are you feeding the same amount as usual? I usually cut the food down a bit as they aren't getting the same excercise, so don't need as much food.

I suppose that you aren't taking the in-season bitch for her usual walks? This is usually why my bitches start to poo in the house. They go in the huff :D

Just a few possibles.

No, the in season bitch isn't being exercised at all, so I will try reducing her food now. 
They are fed twice a day (morning is the main meal with a light meal at tea time).  I haven't fed them anything different from their usual stuff so it can't be that.
Thanks for the suggestions, I'm really hoping this behaviour will stop soon.  Think I might set the alarm clock tonight to get up in the night and make them go out to toilet, see if that helps at all.
Thanks again
Mair

:( Still struggling, anymore suggestions/advice would be really appreciated....Thanks Mair