Well Pophammy and I have just be on a trip to some French pet shops and well....we are amazed
First shop had loads of hamsters mainly syrians. Syrians were large but still appeared peaceful and in males and female tanks. One dom spot female in with two whites got up to reveal a clinging mass of the most lovely pups probably about 10 days old. Another female tucked them in while mum went for a drink. One was the most perfect black band I have ever seen and another was a gorgeous evenly marked back domi spot with a symmetrical white blaze. One was pure black. Hammies were priced at around £7 golden and up to £15 for a LH coloured hammie.
Dragged PH out while plotting how to take mum and babies home in suitcase....
Second shop was shall we say a shock!
One large cage contained all types of hamsters, syrians, WW and I think campbells though likely hybrids. Looked healthy enough and could not believe they were happy as larry all cuddled together. Saw no fighting. Pet shop lady come along with large box of live mealworms and tips scoop of them on to hammies. Hammies of all types run out and grab mealworms and munch them cheerfully. Hammies then snuggle down together again and go to sleep looking somewhat smeared in mealworm juice.
Dragged BigD out muttering about what is all the fuss and why dont we just shove them all together and let them sort it out
So there you are. It must be possible to integrate them young but I am not sure how long this would last. Mums can raise pups under what we would consider stressful conditions and the continent are much more laxed about animal care and pet shops than the british for sure. All the cages we saw were very small, the largest being about a FOP 2 level size. All were barred.The hams were on hay and sawdust.
Some had quite nice type and I would have loved to have brought mum and pups home but well...what can you do