We have three 9 or 10-month old pullets that are going after the two 8-week old "babies" we're trying to introduce. We moved the babies into the hen house in a small enclosure under a heat lamp, but ultimately they need to be able to roam in the hen house/run just like the rest of the bunch. The problem is that every time we let them out in the yard together for some "free range" time, the three older girls go straight for the little ones and peck at them. Is there anything we can do to discourage this? Will the little ones ever be safe?