Termintation and letter

[MonkeyPrincess]

After a month of flip floping, i have decided i am terminating an almost 4 yr old dck. Aggressive behavior (biting especially), child's disobedience, 8 month long potty training struggles, parents inability to control the child at pick up, among other annoyances. i have spoken about this child/family before a few times. Last Friday, the dck bit my daughter on the arm, cut the skin and made a bruise that is still there today. Parents are always told if an incident arises at daycare, so there have been many discussions with the parents about this dck's behaviour. I told the parent that the dck's behaviour is not getting any better and is unacceptable and said if the bevahiour doesn't improve immediately, then they will have to seek other arrangements for her childcare. Well on Monday the dck was a little better behaved, but Tuesday was not so good. general misbehaving, not playing well with other and kicking my 3.5 daughter in the stomach. Mom was told again that any child harming another is unacceptable and she has another incident this week, then they will have to seek other daycare. Wednesday the dck's behaviour was a bit better but today has been horrible. Climbing on furniture, biting another dck this time and knocking the chair over while on time out was enough for me to throw in the towel.

now my question is this...do i give my notice or make termination effective immediately? I have a one week's notice clause, with the certain exceptions like non payment, disrespect, aggressive behaviour of the child, etc. A part of me sympathizes that it might be hard finding another dcp in such short notice. If i give then one week notice of termination, i am afraid that she will hurt another kid again, despite 2 verbal warnings about behaviour have been given in less than a week.

Also, how would you word the termination letter? Do i list all of the reasons or the most severe?