Acans thrive more growing?

[reeferfoxx]

I currently have two colonies. One colony is small with maybe 10 heads on a rock. My other colony has filled up its rock. Question is, does a growing colony thrive more than an established colony? I ask because the smaller colony is constantly displaying its feeding tentacles. Where as the established colony just looks pretty but goes through its inflate/deflate regimen throughout the day. Not so much on the hungry side. Is this normal? Will the colony become stressed eventually? Just making sure it's okay with where its at?