Do you think that a dog can have a phantom simply because there is another one in the house having a pregnancy?  My oldest who has never had a phantom in all her six years has suddenly come into milk and spends all night nesting.  She has been the only one to be bred from before so I was just wondering if this could set her off.

Definitely.

My old bitch Nella would do this every time we had a litter, it didn't matter what stage of her cycle she was at.

When we brought a 5 week old litter of rescue pups into the house, she immediately came into milk and started to feed them, the same happened when our new kitten came home, she started to feed her and did occasionally feed her up until when we lost her last winter.

Some bitch's are very maternal and just the scent of an in whelp bitch in the house will give their hormones a jump start.

Thats why my girl suckles every litter of kittens we have. She also picks them up & carries them to her basket & looks after them untill mum cat takes them back again - lol.

I hope she will look after her pups when they arrive & not wonder what they are because they dont look like little birman kittens!

Yes it's very possible.  My oldest dog as a pup was nursed by both her mother and grandmother