My litter is 16 days old and for the past 2 days they've been struck by a certain 1 or 2 puppies suckling on them creating little bruises or 'love bites' I guess. Mum goes in to feed them approx every 2 hours for 20-25 minutes unless she falls asleep whilst feeding, they're gaining weight. It tends to be after the feed it happens but once disturbed, they'll go to sleep. Do I separate these specific pups? Although they're not showing hunger, do I try get mum to feed for longer?