A tale of two kindergarten classes

This is the first year I've taught as young as kindergarten, and it's been a bit of a classroom management challenge. I talked to the kindergarten teachers and got some suggestions before the year started, and I've been using a preschool curriculum (with modifications to hit more of the standards), so I feel like I'm teaching appropriate to the level. One of the classes has been fabulous all year long. The other two have given me and the art teacher plenty of trouble. Lately, though one has been rapidly improving. A comparison:

• Both changed the configuration of the classroom--doesn't that just make it feel better?!
• The unimproved class is still using the same clip chart from the beginning of the year; the improved class has completely revamped their discipline system
• The unimproved class's teacher very rarely communicates with me on discipline; the improved class's teachers have emailed me to give feedback (I asked for it) and explained their new system and how I can use it.
• The unimproved class's teacher starts music class with a talk to her students on how rules stay the same for "specialist" teachers as for her--and while she says this I see students making faces and playing around. The other class's teachers use more age-appropriate language and a significant amount of sign language to communicate expectations.

This school has a tendency to hire mostly inexperienced teachers, and so discipline is difficult when I only see the students forty minutes every week. But I wish the other kindergarten teacher would take some cues from the other two. I try to keep class moving and quickly move on to new activities, but it's very difficult when I have to stop frequently to give new directions.

Has anyone else experienced difficulties with teaching the little ones? Is there anything that has worked for you?