Agreed that a good mom will not reject babies just because you touched them. I know you're excited with having your first babies and all, just don't go overboard with pla=ying with them.
Probably the biggest risk is becoming attached to the feeders. Much harder to feed off a animal you've been playing and interacting with than simple livestock.
As for checking them over and counting, as soon as mom has cleaned up the litter (not all bloody and slimey) you can do a head count. On cleaning day when I'm building / adjusting my 0.2.24 raising tubs, I move the female(s) first, then count the babies as I move them over also.
When I grab groups of feeders, I never have problems returning whatever is left to whoever is available. I do keep sizes similar. For example, I'll pull several litters of pinky rats to feed my hatchlings. Not even really paying attention to exactly how many I have. I do try to make sure I pull too many (saves trips) When done feeding the leftover pinky rats go back to however many moms necessary to not go over 1/12 ratio. Yeah mom's can hand;e more but by keeping limiting the ratio to 1/12 max, my babies do well.
I do the same pull/feed/return process with larger pre-wean feeders for my larger subadult snakes. My feeding days are typically the two or three days before cleaning day so on cleaning day the colony size is at it's lowest point of the week....fewer animals to move and easier to consolodate into fewer tubs leaving open slots for birthing tubs.
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Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count (05/26/2009):
36.51 BRB
29.42 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 

